This expression, The Angel Of The Lord [Jehovah] occurs over 100 times in the Old Testament, meaning messenger or agent. Sometimes it describes an angelic messenger, and sometimes it refers to the Lord Himself. The context easily makes it clear, which is indicated. The context of Genesis 16:7, for instance, clearly proves The Angel of the Lord is the Lord Himself. None but a Divine Person could say, "I WILL multiply thy seed exceedingly, that it shall not be numbered for multitude." (Gen. 16:10).
That Hagar recognized this is clear. We read, "And she called the name of the LORD [Jehovah] that spake unto her, Thou God seest me: for she said, Have I also here looked after Him that seeth me? Wherefore the well was called BEER-LAHAI-ROI [margin, the well of Him that liveth and seeth me]." (Gen. 16:13, 14).
A striking case of the Angel of the Lord being Jehovah Himself is seen when the Lord called to Moses out of the burning bush, saying, "I AM the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob." (Ex. 3:6).
There is a very beautiful variation of this title found in Isa. 63:9. "In all their affliction He was afflicted, and THE ANGEL OF HIS PRESENCE saved them: in His love and in His pity He redeemed them; and He bare them, and carried them all the days of old."
None but a Divine Person could use words such as these. Referring to a day yet future, we read, "In that day shall the LORD defend the inhabitants of Jerusalem: and he that is feeble among them at that day shall be as David; and the house of David shall be as God, as THE ANGEL OF THE LORD before them." (Zech. 12:8).