Question: Who is "the Angel of the Lord" mentioned so many times in the Bible?
Answer: Reference is made to "the Angel of the Lord" (meaning the Messenger of Yahweh, or Jehovah) fifty-two times in the Old Testament (called "the Angel of God" another nine times). The appearances stop, as the New Testament era begins (once Christ has come in the flesh).
The vast majority of evangelical scholars take this Being to be God the Son, appearing before His incarnation. (The NKJV frequently capitalizes "Angel" in this context, treating it as a reference to deity.)
Malachi seems to give us a confirmation of this view. When he prophesies of the coming of Christ, he calls Him "the Messenger [same word, Angel] of the Covenant, saying, "‘The Lord, whom you seek, will suddenly come to His temple, even the Messenger of the covenant, in whom you delight. Behold, He is coming,' Says the LORD of hosts".
These appearances of God in physical form are called theophanies. And I've also included five instances where the word "angel" is not used, as they seem to refer to the same Being.
Numerous characteristics and actions ascribed to Him are ones that can only apply to God, as you'll see if you examine the following in context. So, if He is an "angel" (or messenger), it is only by His temporal office or role at the time, not by His actual and eternal nature, as if He were a created being.
There could be other examples that I've missed, but here are the main ones. The Angel of the Lord appeared:
1) To Hagar, in the wilderness, prior to the birth of Ishmael (Gen. 16:7, 9, 10, 11).
2) To Abraham as a "Man," in the company of two angels (Gen. 18:1-2).
3) To Hagar again, after the birth of Ishmael (Gen. 21:17).
4) To Abraham on Mount Moriah, when he was about to sacrifice his son in obedience to God (Gen. 22:11, 15).
5) To Jacob, when he was living with his uncle Laban (Gen. 31:11, 13).
6) To Jacob as the "Man" who wrestled with him (Gen. 32:24-32).
7) Jacob identifies Him as "the Angel" who redeemed Him (Gen. 48:15-16).
8. To Moses in the burning bush (Exod. 3:2, cf. vs. 14).
9) To Israel in the pillar of cloud and fire that went before them in the wilderness (Exod. 14:19).
10) To the mercenary prophet Balaam, when he was going to see the Moabite king Balak (Num. 22:22, 23, 24, 25, 26, 27, 31, 32, 34, 35).
11) God promises Israel that "My Angel" will go before them as the conquer the land of Canaan (Exod. 23:20-21; 32:34; cf. Isa. 63:9, where He is called "the Angel of His Presence").
12) To Joshua as a "Man" who called Himself the "Commander of the army of the Lord" (Josh. 5:13-15).
13) To the Israelites after they entered Canaan but failed to completely destroy or drive out the Canaanites, as God had commanded (Jud. 2:1, 4).
14) Spoken of in the song of Deborah, after Barak had defeated the Canaanite army of King Jabin (Jud. 5:23).
15) To Gideon, to commission him to lead Israel against the Midianites (Jud. 6:11, 12, 20, 21, 22).
16) To Manoah and his wife, with regard to the coming birth of Samson (Jud. 13:3, 6, 9, 13, 15, 16, 17, 18, 20, 21).
17) Referred to when a woman appeals to David to forgive his son Absalom (II Sam. 14:17, 20).
18) Referred to when Mephibosheth appeals to David (II Sam. 19:27).
19) When God was angry with Israel and threatened to destroy Jerusalem by the Angel of the Lord (II Sam. 24:16; I Chron. 21:12, 15, 16, 18, 30).
20) To Elijah, late in his prophetic ministry, to direct his dealings with Ahaziah and Jehoram, kings of the northern kingdom of Israel (II Kgs. 1:3, 15).
21) As the One to bring destruction upon the Assyrian army (II Kgs. 19:35; Isa. 37:36).
22) Referred to as protecting those who fear God (Ps. 34:7).
23) Referred to when David prays for the judgment of God upon his enemies (Ps. 35:5, 6).
24) To the three Hebrews thrown into the fiery furnace (Dan. 3:24-25).
25) To Daniel (possibly) as the "man" who appeared to him as he sat by the Tigris River (Dan. 10:5-6).
26) In a vision of the prophet Zechariah (Zech. 1:11, 12).
27) In another vision of Zechariah concerning Joshua the high priest (Zech. 3:1, 5, 6).
A question arises from all of this: If the Son of God had the power to appear in the form of man, why was it necessary for Him to go to the trouble of being born of a virgin into the human family. The answer is that it was necessary for Him to actually be Man, not simply appear as one, in order to take our place and pay our debt of sin.
The Bible says: "Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil, and release those who through fear of death were all their lifetime subject to bondage" (Heb. 2:14-15).
He is "the Man Christ Jesus" (I Tim. 2:5), not simply a spirit manifestation (Lk. 24:39). It was prophesied that the "seed of the woman" would crush the serpent's head (Gen. 3:15). And to that end, "The Word [Christ] became flesh, and dwelt among us" (Jn. 1:14; cf. Matt. 1:21-23). For His willingness to do this in order to redeem us, we shall eternally praise Him!