This is the famous Seventieth Week of Daniel, the seventieth seven, the "Tribulation".

This important passage should be interpreted in its plain, natural, literal sense, taking care to avoid speculation, allegorization, application of symbolism or spiritualization.  Any other interpretative schema other than literal leaves this critical passage and this entire section (Da 9:24-27) open to a variety of interpretations limited only by the expositor's imagination.  As discussed below, the natural and most logical interpretation is to take Daniel 9:27 literally. The literal interpretation indicates the events described are yet future, for one cannot identify a historical 7 year period which completely explains all the events. This verse describes what expositors have referred to as The Tribulation. It should however be emphasized that there is not specific Scripture that designates this entire seven year period as the tribulation. 

*Note: The word "Tribulation" is never specifically used in Scripture to designate the last 7 years, Daniel's 70th week, but will be used in these notes because the term is so firmly entrenched in Christian jargon.

The Bible Knowledge Commentary addresses the faulty logic of amillennialists who refuse to accept a gap between Daniel 9:26 and Daniel 9:27 writing that...

Amillenarians teach that Christ’s First Advent ministry was in the 70th “seven,” that there was no interval between the 69th and 70th “sevens,” and that the six actions predicted in Daniel 9:24 are being fulfilled today in the church. This view, however, (a) ignores the fact that verse 26 says “after the 62 ­sevens, ‘ ”not “in the 70th ­seven, ‘” (b) overlooks the fact that Christ’s ministry on earth was three and one-half years in length, not seven, and (c) ignores the fact that God’s six actions pertain to Daniel’s “people” (Israel) and His “Holy City” (Jerusalem), not the church. (Walvoord, J. F., Zuck, R. B., et al: The Bible Knowledge Commentary. 1985. Victor or Logos)

John MacArthur discusses the gap between the 69th and 70th weeks writing...

There is a gap between the sixty-ninth and seventieth weeks prophesied in Daniel 9:24-27. During that gap Christ was crucified and the Temple destroyed--a period of approximately forty years. Scripture does not indicate the length of the gap, though we do know it will last until the Antichrist comes to confirm a covenant with Israel (Da 9:27). Its undetermined length ought not to trouble us: many prophecies in Scripture contain such gaps.

1. Isaiah 9:6--"Unto us a child is born, unto us a son is given, and the government shall be upon His shoulder. " While that prophecy speaks both of Christ's birth and right to govern, a gap exists between the two.

2. 1 Peter 1:10, 11 (note)--A great period of time exists between the first and second comings of Christ--a period unperceived by the Old Testament prophets.

3. Luke 4:18, 19--In those verses Jesus quoted the portion of Isaiah 61:1-2 that applies to His first advent, but not that which applies to His return as Judge. He recognized the gap between those two appearances.

4. Eph 3:9 (note)--That gap is identified as the Church Age, which Paul called "the mystery, which from the beginning of the ages hath been hidden in God. " It's a historical parenthesis within the seventy weeks determined for Israel.

If the seventy weeks of Daniel were 490 consecutive years, there would be no question when our Lord would come again. But because it was intended to be of indeterminate length our Lord said, "Of that day and hour knoweth no man, no, not the angels of heaven, but my Father only" (Mt. 24:36; cf. Acts 1:7). (Ref)

Click for a more detailed discussion of the rationale for the interpretation of the gap between the 69th and 70th weeks and the conclusion that the 70th has to be a yet future time period. As discussed in the explanatory notes it is not uncommon for prophetic passages to demonstrate a significant "pause" or "gap" in regarding partial and complete fulfillment.

Walvoord explains the interpretation of Daniel 9:27 this way...

If the expositor desires to follow the text meticulously, however, there is really no alternative but to declare the entire seventieth seven future, for there has been no seven-year period fulfilling the events of prophecy, however labored the interpretation. This is usually conceded by those who make the last seven years an indefinite period which allows for still future interpretation. (John Walvoord:  Daniel: The key to Prophetic Revelation online)

And he will make a firm covenant (Isaiah 42:6; 53:11; 55:3; Jeremiah 31:31, 32, 33, 34; 32:40, 41, 42; Ezekiel 16:60, 61, 62, 63; Mt 26:28; Ro 5:15,19; 15:8,9; Gal 3:13, 14, 15, 16, 17; He 6:13, 14, 15, 16, 17, 18; 8:8, 9, 10, 11, 12, 13; He 9:15, 16, 17, 18, 19, 20,28; 10:16, 17, 18; 13:20,21) (Mt 27:51; He 10:4-22)

He - Who is he? Applying the accepted rule of interpretation and observing the text for the nearest antecedent of the pronoun he (without bias or influence by other "experts") one most logically links he with the prince who is to come (Daniel 9:26). This is also the conclusion reached by most conservative evangelical commentaries who go on to identify him as the Antichrist who comes out of the fourth beast (fourth kingdom) with 10 horns in Daniel 7 (The Revived Roman Empire).

We know that the prince's people destroyed Jerusalem in 70 A.D., and thus we can deduce that this coming prince has his ancestral roots in the ancient Roman Empire and is thus part of what commentators refer to as "the revived Roman Empire", the final human world government described in more detail in Romans 7 (see Da 7:7, 19). In the Revelation of Jesus Christ, John records his vision...

And he stood on the sand of the seashore. And I saw a beast ("the prince who is to come", the Antichrist) coming up out of the sea, having ten horns and seven heads, and on his horns were ten diadems, and on his heads were blasphemous names. (See notes Revelation 13:1; see also the study of The Beast; and Beasts, Heads, and Horns)

Other identifications have been proposed including Antiochus Epiphanes (Montgomery) who feels that this prophecy was fulfilled in the second century before Christ noting how apostate Jews co–operated with Antiochus (see 1 Mac 1:11-15).

E. Young and P. Mauro interpret the he as a reference to the Messiah primarily because the entire prophecy is about the Messiah and the premise that there is no "future 'prince' making a covenant with" Israel. This interpretation makes little sense for the new covenant in His blood is an everlasting covenant, not a seven year covenant and not a covenant which He will never break for God is a covenant keeping God! How can the reference be to Christ when we have just been introduced to the prince who is to come which describes one out of the Roman empire? Christ did not come from the Roman empire. Furthermore, when did Christ make a firm covenant with many Jews for one week (seven year period)? And how can it be said of Christ that “in the midst of the week” He caused the sacrifices to cease? Sacrifices continued in the Temple some 40 years after Messiah was cut off, well past the 7 years of the 70th Week.

Harry Ironside agrees that he is not the Messiah writing...

Ere closing I briefly notice a rather peculiar interpretation which is frequently given to the 27th verse. It is said that the Lord Jesus is Himself to be the prince that shall come who confirms the covenant for one week. His own crucifixion is supposed to be the event which caused the sacrifice and oblation to cease. But neither chronologically nor doctrinally will this stand for a moment, if examined in the light of other scriptures. With whom did the Lord Jesus ever confirm a covenant for seven years? His precious blood is called ”the blood of the everlasting covenant;” not a covenant for one week of years. We may rest assured it is not Messiah at all, but the blasphemous prince who is yet to come, who will fulfil what is predicted in this verse.

How near this world may be to the actual entering upon all these things no man can say, but it is the part of wisdom to learn from the prophetic Scriptures, and to turn now to Him who alone can save; to own Him as Redeemer and Lord, and thus be certain of being caught up to meet Him when He comes in the clouds, ere the time comes for His righteous judgment to be poured out upon this poor world. (Ironside, H. A. Lectures on Daniel the Prophet. 1911)

The pronoun He has even been interpreted as a week by some who take he as neuter (not masculine). But interpretation of he as week makes absolutely no sense in the context.

In Revelation John gives us a fascinating description of a man revealed upon opening the second seal on the scroll...

And I looked, and behold, a white horse, and he who sat on it had a bow (a symbol of strength - Job 29:20, 30:11); and a crown was given to him; and he went out conquering, and to conquer. (see note Revelation 6:2)

Note the similarities of this man to the Christ -

(1) Riding a white horse (Re 19:11-note)

(2) Wearing a crown (a stephanos {note} not a diadema, although Christ also wore a stephanos in Mt 27:29, John 19:2, 5) (Re 19:12-note)

(3) Overcome - both this man and Christ are "overcomers" (Jesus said "take courage, I have overcome the world" in Jn 16:33, cf 1Jn 4:4, Re 3:21, 17:14- see note Re 3:21; 17:14)

The identity of this man in Re 6:2 (note) is definitely not the true Christ, for in fact it is the Lamb, the Messiah Who was worthy to open and did open the scroll from His Father (Re 5:2, 4, 7, 9, 12, 6:1 - see notes Re 5:2; 5:4; 5:7; 5:9; 12; 6:1). This cannot be Christ riding forth, for He must open the remaining seals! This man carries a bow, whereas Christ carries a sword (Re 2:12, 19:15-see notes Re 2:12; 19:15). This rider is alone, whereas "the armies which are in heaven, clothed in fine linen, white and clean, were following Him (Christ) on white horses." (Re 19:14-note) Finally, notice that Christ rides forth on a white horse at the end of the Great Tribulation, but this rider comes forth at the beginning of the Seventieth Week of Daniel (although admittedly when during this first 3.5 years this specific event occurs cannot be accurately determined from Scripture). In light of this description, who might the world think is riding forth here in Re 6:2 (note)? This is almost certainly the "Beast" of Revelation the the Antichrist (anti = instead of or against + Christos = anointed one) who comes on the world scene at the beginning of the Tribulation (see John 5:43 below)

Notice that although the man in Re 6:2 (note) is to conquer he has a bow but no arrows. and in this way he resembles Antiochus Epiphanes (see Daniel lecture and additional discussion) who seized "the kingdom by intrigue" and practiced "deception, and... (gained) power with a small force of people" and in so doing pre-figured the Antichrist (see Da 11:21, 22, 23 - See Dr Walvoord's comments) A bow without arrows may indicate that the Antichrist will conquer more by shrewd statesmanship or deceptive diplomacy than by brute force. Daniel in fact describes him as a man possessing "a mouth speaking great things" (Daniel 7:8  - See Dr Walvoord's comments) , yet with an intimidating force at his back. He will be able to negotiate concessions for Israel - security, permission to rebuild their beloved temple, and the right to worship with Temple sacrifices.

This man, the Antichrist will orchestrate a peace treaty with Israel for seven years and thus will initially be a hero to the Jews. Without speculating too much, it is very easy to see how this can happen for in our day, for Israel is internationally isolated and is desperately seeking support against the jihadist pressure of the Muslim neighbors, as well as continuing to distrust the Russians out of fear a potential threat coming from the north (direction of Russia).

Make a firm covenant - What is the idea of make...firm? Daniel could have recorded the usual OT phrase "cut a covenant" but as discussed below the use of this phrase gives some insight into the Antichrist's modus operandi.

Make a firm (01396) (gabar) is a primary verb commonly associated with warfare and with strength and vitality of a successful warrior.  Some OT uses (contexts) of gabar convey the sense of showing oneself as arrogant or overbearing as is one whose attitudes and actions reflect hubris and pride (cf the Antichrist's "boastful words" {although not the word gabar} in Daniel 7:11, 20 - See Dr Walvoord's comments, see also notes on Revelation 13:5). The idea inherent in gabar is to be strong, to triumph over or to prevail, thus picturing superior strength over someone or something. For example, gabar in Exodus 17 vividly portrays this idea...

So it came about when Moses held his hand up, that Israel prevailed (gabar), and when he let his hand down, Amalek prevailed (gabar). (Exodus 17:11)

Covenant (01285) (berith/beriyth) (see in depth study beginning with Covenant in the Bible) (Septuagint - LXX translates covenant with Greek noun diatheke {see study}) as discussed elsewhere is the most solemn and binding agreement known in the ancient world. Someone has written that "There is no firmer guarantee of legal security peace or personal loyalty than the covenant". The greatest tool for covenant making came to be the written document on which the words of the covenant, its terms in the form of promises and stipulations, were spelled out, witnessed to, signed and sealed. Such covenant documents abound in ancient records.

With the many -

In context refers to the Jews or Israel and is not a general reference to any group.  Comparing with other passages one notes that the many refers to Jews in Da 11:33, 39 (Dr Walvoord's comments) and Da 12:3 (Dr Walvoord's comments).

What will the many do? Covenant  in our modern world has lost much of its Biblical meaning (cf how tragically frequent marital partners break their covenant - see Covenant: As It Relates to Marriage) but in the context of the Bible, covenant has always signified a solemn, binding agreement and as such represented the entering of two parties into an intimate, ostensibly indissoluble agreement. And so by entering into this covenant with the Antichrist, Israel will embrace the this prince who is to come as a veritable "savior" who has been able to accomplish what heretofore all others have failed to produce - "Peace" in the Middle East. This prince becomes their "political messiah". Israel's desperate desire for peace, security and safety will play into the hands of Antichrist, who will convince them and the world that he can provide this peace.

And yet one still has to wonder, how can the world and Israel be so totally deceived, especially in light of the fact that we hear many non-believers talking about the Antichrist. But if we recall from history, this scenario is precisely what happened before the outbreak of World War II. Adolf Hitler had even spelled out in detail his plans for conquest in his book Mein Kampf, which had been published more than a decade before World War II began. Yet, incredibly, Britain and France persisted in believing Hitler’s false claim to be a man of peace, passively standing by as he reoccupied the Rhineland (demilitarized after World War I) and thus abrogated the Versailles Treaty. Desperate to appease Hitler and avoid war, British Prime Minister Neville Chamberlain met with the Nazi dictator at Munich in 1938. Upon his return to England, Chamberlain triumphantly waved a piece of paper containing a worthless pledge of peace from Hitler which he claimed guaranteed “peace with honor … peace for our time.” When Winston Churchill (one of the few never taken in by Hitler) rose in the House of Commons to declare that England had suffered a total, unmitigated defeat he was shouted down by angry members of Parliament. The deception was nearly universal as almost everyone misread Hitler’s intentions. Only after he had invaded Poland in September, 1939 did the allies finally acknowledge the truth of his evil plan to conquer the world, but by then it was too late to avoid the catastrophe of the Second World War.

The Bible repeatedly warns of the deadly lure of false peace offered by false prophets, God declaring...

they have healed the brokenness of My people superficially, Saying, 'Peace, peace,' But there is no peace. (Jer 6:14, cp Jer 8:11, 14:13)

False prophets spoke of peace in Jerusalem even while faced with the threat of Babylon. In this setting...

The Lord replied, “The prophets are prophesying falsehood in My name. I have neither sent them nor commanded them nor spoken to them; they are prophesying to you a false vision, divination, futility and the deception of their own minds” (Jer 14:14)

Paul describes the deceitfulness of this future false peace that is a harbinger of the Day of the Lord writing...

While they (unbelievers) are saying, "Peace and safety!" then (when? while they are saying "peace and safety") destruction will come upon them suddenly like birth pangs upon a woman with child; and they shall not escape. (see note 1Thessalonians 5:3).

In John 5, Jesus predicted this Jewish "apostasy" (which I think correlates well with "the apostasy" that Paul describes in 2Thes 2:1-4 (Dr Walvoord's comments) that precedes the Antichrist's claim of deity in the midst of the Temple in Jerusalem)...

I have come in My Father's name, and you do not receive Me; if another shall come in his own name, you will receive him. (John 5:43)

Comment: This was partially and literally fulfilled in the first century, as the Jewish historian Josephus, recorded a string of messianic pretenders in the years before 70AD, the fall of Jerusalem and sacking of the Temple. Jesus was predicting that though the Jews would not follow Him, they sadly and somewhat ironically would follow false messiahs, the final prince who is to come being the ultimate false messiah, which of accounts in part for his name of Antichrist = instead of Christ, in place of Christ, against Christ

Now one should understand that while most of Israel at this time is still unbelieving, God always has a faithful Jewish remnant, who confess their sin, and place their faith in the Messiah.

Harry Ironside explains that...

The many, that is the apostate mass of the (Jewish) people, will enter into covenant relations with the prince whose people formerly were the instruments of the destruction of their city. That is, this great blasphemous Roman leader will guarantee protection and freedom of religious worship to them for seven years, in return for which they will promise allegiance to him as their sovereign. In the midst of the week (that is, after three years and a half) he will violate his part of the covenant, and cause the sacrifices and oblations to Jehovah to cease. Idolatry of the most dreadful kind will be forced upon them. The direct result of which will be to distinguish the remnant from the mass, and thus to bring in the Great Tribulation which will continue for forty-two months,—“a time, times, and half a time,” or 1260 days. (Ironside, H. A. Lectures on Daniel the Prophet. 1911)

To reiterate, the Covenant the Antichrist makes with Israel marks the onset of the Seven Year period referred to as "The Tribulation" and is evidently a covenant of protection and of religious freedom under which Israel is free to re-establish their system of sacrifices.

Where will the Jews perform the sacrifices? The answer is that sometime either before or during this first 3.5 years of the Tribulation (Scripture is not dogmatic) the Jewish Temple is rebuilt on the Temple Mount in Jerusalem and sacrifices are resumed. The only acceptable site for the Jewish Temple is "Temple Mount", which in 2007 is the site of the Dome of the Rock and under Muslim control. Clearly there must be a radical shift in policy to allow the Temple to be rebuilt, and this may be one of the Antichrist's first major breakthrough, as he is able to bring about "peace" in the Middle East, something the world is now crying for almost daily in newspapers and newscasts. John clearly indicates the presence of a Jewish Temple in the end times recording that...

There was given me (John) a measuring rod like a staff; and someone said, "Rise and measure the temple of God, and the altar, and those who worship in it. And leave out the court which is outside the temple, and do not measure it, for it has been given to the nations; and they will tread under foot the holy city for forty-two months. (See notes Rev 11:1; 11:2).

Note that Revelation 11 and 12 are vitally important chapters regarding the timing of events in Daniel's Seventieth Week and should be carefully studied by all believers so that we might be able to give unbelievers an account of the hope that we possess (1Pe 3:15-note). As you read these chapters you will observe repeated references to a 3.5 year period, one reference referring to events that occur in the first 3.5 years of the Tribulation but most referring to events in the second half of the Tribulation. Below is a table summarizing the various time phrases representing either the first half or second half of this last Seven Year Period. The discerning reader should examine these passages in context, and interpret literally where possible (John's language in Revelation 12 is very figurative, but do not forget the basic principle that even figurative passages have a "literal" meaning and cannot be wildly spiritualized or allegorized!) allowing the Spirit to lead you into all the truth (see 1John 2:27 where "anointing" is a reference to the Spirit indwelling every believer, see Ro 8:9 -note)