Several commentators point out that in the OT a census was typically conducted to muster an army or to assess its strength. Thus they see the census of Revelation 7 as a parallel to Numbers 1. Revelation 7, according to these commentators, is about mustering an eschatological army of witnesses. This view is bolstered by some verbal parallels between the two chapters: εκ φυλης in Revelation 7:5-8 corresponds with εκ της φυλης in Numbers 1:21-4; "of the sons of Israel" is repeated in both chapters; and both lists mention Joseph as a tribe. The fact that Revelation 14 indicates that all of them are men strengthens the military view of this census.
Those taking this view typically understand the 144,000 of Revelation to be symbolic of the church, but this is doubtful. Revelation 7 divides its attention between Israel on the earth of a specific number and a numberless multitude from all nations in heaven. Israel is clearly the focus in the first part of chapter 7 because of the detailed listing of the tribes. One could argue that the census and listing of tribes is just a device to cause the reader to think of God mustering an army, but this expedient is not necessary for those who believe Israel still has a role to play in the future. Given the OT prophecies of Israel fulfilling its role as a witness to the nations (Ex. 19:3-6; Deut. 4:5-8), and given the partial fulfillment already in the NT (Matt. 15:24; Acts 1:6-8; 2:5, 41; 9:15; 10:44-48; 13:1-3), it is more natural to see this army as an army of witnesses sent to the nations. The numbering of 12,000 from every tribe could well signify completeness, though this need not rule out numerical prediction. Because of God’s sovereignty, symbol and reality can often coincide. If the passage is meant to parallel Numbers 1, the smallness of the numbers in Revelation may point up the fact that it is a remnant of Israel which God is restoring.
Revelation 14 returns to the 144,000. It seems that this chapter looks forward to the end when Christ is enthroned on Mount Zion. This army of Israelite men accomplished what the army of Numbers 1 failed to achieve: they are in the land, indeed on Mount Zion. They have remained faithful, as symbolized by their virginity and as evidenced by their honesty. This latter point especially contrasts with Numbers because the complaints that arise against God in this book and give rise to rebellion are, in fact, lies against God. Note also the difference in the task of these armies. In the OT the armies of Israel were to conquer Gentile nations both in judgment on them and to give Israel space to live out its witness to them; in the NT the army of Israel is purely a force of witnesses (the judgment is being carried out immediately by God himself). As Numbers progresses, it will begin to record the failures of Israel, but in the end, the text of Revelation assures us, God’s people will fulfill their role as witnesses to God, and they will live in the promised land forever.
 Beale and McDonough, "Revelation," in Commentary on the New Testament Use of the Old Testament, 1107; cf. Osborne, BECNT, 313.
 Beale and McDonough, 1107.
 There is debate about whether Mount Zion in this passage is in heaven or on earth. The fact that a voice is heard from heaven favors an earthly scene. Osborne, BECNT, 525; cf. Thomas, 2:190.
 Again, symbol and reality do not need to be set at odds. There is no reason to think that the 144,000 were not actually virgins. The virginity of the 144,000 may strengthen the thesis that these men were mustered for service in the Lord’s army, for the OT indicates that soldiers refrained from sexual activity while in the field (Deut. 23:9-10; 1 Sam. 21:5; 2 Sam. 11:8-11). Osborne, BECNT, 529. Thomas notes this interpretation but dismisses it because he finds the military imagery inconsistent with martyrs who do not resist. Thomas, 2:196. But in reality this need not be inconsistent. The army mustered in Revelation need not fight in the same way as the army mustered in Numbers. They can be an army of martyred witnesses.