And the sixth angel poured out his bowl upon the great (spiritual) river, the Euphrates; and its (life-giving, spiritual) water was dried up, that the way might be prepared for the (spiritual) kings from the east.  And I saw coming out of the mouth of the dragon and out of the mouth of the beast and out of the mouth of the false prophet, three unclean spirits like frogs; for they are spirits of demons, performing signs, which go out to the kings of the whole world (earth), to gather them together for the war of the great day of God, the Almighty.  (“Behold, I am coming like a thief.  Blessed is the one who stays awake and keeps his garments, lest he walk about naked and men see his shame.”)  And they gathered them together to the place which in Hebrew is called Har-Magedon.  (Megiddo was one of the cities given to the sons of Manasseh by Joshua “but the sons of Manasseh could not take possession of these cities, because the Canaanites persisted in living in that land”, Joshua 17:12-13, Judges 1:27, 2:1-3.  Thus the mountain of Megiddo represents those places where the sons of Israel have not come to possess the land.  Precisely at those places they will be destroyed by the wrath of God.  Cf. also 2 Chron 35:20-24 where Josiah, a godly king, was destroyed by God at Megiddo for interfering with what God was doing through the king of Egypt.)
Revelation 16:12-16

 Hear this, O foolish and senseless people, who have ears, but hear not.  “Do you not fear Me?” declares the LORD.  “Do you not tremble in My presence?  For I have placed the sand as a boundary for the sea, an eternal decree, so it cannot cross over it.  Though the waves toss, yet they cannot prevail; though they roar, yet they cannot cross over it.  (I.e., the sand restrains the sea).  But this people has a stubborn and rebellious heart; they have turned aside and departed.”  (I.e., they have not restrained that evil in the world of which the sea is a type).
Jeremiah 5:21-23

 Let no one in any way deceive you, for the day of the Lord will not come unless the apostasy comes first, and the man of lawlessness is revealed, the son of destruction, who opposes and exalts himself above every so-called god or object of worship, so that he takes his seat in the temple of God, displaying himself as being God.  Do you not remember that while I was still with you, I was telling you these things?  And you know what restrains him now (most literally, “holds him fast”), so that in his time he may be revealed.  For the mystery of lawlessness is already at work; only he who now restrains will do so until he is taken out of the way…
2 Thessalonians 2:3-7

 The true saints of God through the Spirit of Christ within them are what hold fast and restrain the man of lawlessness–through their prayers to God and righteousness (cf. Gen 18:22-33, 19:23-29).  But when the apostasy comes and so many have fallen away, then the Spirit of Christ will depart from His temple just as in the days of Ezekiel.  In this way the great spiritual river Euphrates is dried up so that the man of lawlessness may be revealed.