Who is the Angel of the Covenant (Mal. 3:1)?
Some say it is YHWH and others say it is the return of Elijah.
[Counterfeit] House of Aaron founder and false prophet Maurice Gledenning claimed to be the last days Elias (Elijah) and to be the messenger of the covenant from Malachi 3-4 saying:
"...that those of the House of Ephraim may know that I am the one spoken of by the prophets who should come to restore all things appointed unto me, I do now declare unto you that I am Elias who should come in the last days to restore unto Ephraim the House of Levi" (Levitical Writings 166:1)
“Behold, I send my messenger, and he will prepare the way before me. And the Lord whom you seek will suddenly come to his temple; and the messenger of the covenant in whom you delight, behold, he is coming, says the LORD of hosts.
The first "messenger" mentioned is presumably the 144,000, who are the end-time Elijah, in the same way John the Baptist was an Elijah.
The lower-case Lord is Yeshua, as well as the "angel/messenger of the covenant in whom is delight."
"Angel" simply means messenger, so I would argue it could be Yeshua; not a very popular idea, but it fits perfectly.
Incidentally, "The angel of the Lord" is presumably the pre-incarnate Yeshua as well, acting as the Lord's vessel for communication and manifestation.
The Zohar mentions the Angel of the Covenant in three passages:
AND HE SAID: I WILL CERTAINLY RETURN UNTO THEE WHEN THE SEASON COMETH ROUND, ETC. (Gen. 18:10) R. Isaac said: ‘Instead of “I will return”, we should have expected here “he will return”, since the visitation of barren women is in the hand of the Almighty Himself and not in the hand of any messenger, according to the dictum: “Three keys there are which have not been entrusted to any messenger, namely, of child-birth, of the resurrection, and of rain.” But the truth is that the words “I will return” were spoken by the Holy One, blessed be He, who was present there. This is corroborated by the use here of the term vayomer (and he said). For it is to be observed that wherever the verb vayomer (and he said), or vayiqra (and he called), occurs without a subject, then the implied subject is the Angel of the Covenant and no other. Examples are: “And he said, If thou wilt diligently hearken etc.” (Ex. XV, 26); also: “And he called unto Moses” (Lev. I, 1); also: “And unto Moses he said” (Ex. XXIV, 1). In all these passages, as well as in our present passage, the unspecified subject of the sentence is the Angel of the Covenant. In all these passages, as well as in our present passage, the unspecified subject of the sentence is the Angel of the Covenant.
R. Eleazar said: ‘Observe that, as has been stated elsewhere, our father Abraham, after he acquired Wisdom, determined to keep separate from all other nations and not to enter into matrimonial alliance with them. Hence we read: AND I WILL MAKE THEE SWEAR BY THE LORD, THE GOD OF HEAVEN AND THE GOD OF EARTH, THAT THOU SHALT NOT TAKE A WIFE FOR MY SON OF THE DAUGHTERS OF THE CANAANITES, ETC . The words “daughters of the Canaanites” are parallel to the expression “daughters of a strange god” (Mal. II, 11). So, too, the word “I” (Anokhi) which follows is a reference to the Deity, as in the verse, “I (Anokhi) made the earth.” The purpose of this injunction was to save Isaac from being defiled by them. For whoever impairs the sanctity of the holy covenant by contact with a woman of an idolatrous nation causes the defilement of a certain other place, alluded to in the passage, “For three things the earth doth quake, etc.” (Prov. XXX, 21). And although Abraham adjured his servant by the holy covenant, he did not feel satisfied until he had made supplication on his behalf to the Holy One, blessed be He, saying: THE LORD, THE GOD OF HEAVEN... MAY HE SEND HIS ANGEL BEFORE THEE, ETC. , to wit, the angel of the covenant”, so that the covenant might be preserved in its sanctity, and not be defiled among the nations. He continued: BEWARE THOU THAT THOU BRING NOT MY SON BACK THITHER . Why so? Because Abraham knew that none among those nations had knowledge of the true God like himself, and so he desired that Isaac should not settle among them, but should continue to dwell with him, so that he might constantly learn the ways of the Holy One, and turn neither to the right nor to the left.’ R. Jose said: ‘Of a certainty the merits of Abraham stood his servant in good stead, for on the very day on which he set out he reached the fountain, as it says, AND I CAME THIS DAY UNTO THE FOUNTAIN .
R. Isaac rose from his bed one night to study the Torah. R. Judah, who happened then to be in Caesarea, said to himself at the same time: ‘I will go and join R. Isaac in the study of the Torah.’ He accordingly set out along with his youthful son Hizkiah. As he was nearing R. Isaac's threshold he overheard him expound the verse: “And it came to pass after the death of Abraham, that God blessed Isaac his son; and Isaac dwelt by Beer-lahai-roi” (Gen. XXV, 11). ‘The connection between the two parts of this verse’, he said, ‘is obscure, but may be explained as follows. It was necessary that God should bless Isaac, because Abraham had not blessed him, and the reason why Abraham had not blessed him was to prevent that blessing being transmitted to Esau. Hence the task of blessing fell, so to speak, to the Almighty. The text thus continues: “And Isaac dwelt by Beer-lahai-roi” (lit. the well of the living and seeing one), that is, as the Aramaic paraphrase has it, “the well where appeared the Angel of the Covenant”, to wit, the Shekinah, to which Isaac became attached, thereby drawing upon himself the blessing of the Almighty.’ At that point R. Judah knocked at R. Isaac's door, entered the room and joined him. R. Isaac said: ‘Now, the Shekinah herself is in our presence.’ Said R. Judah: ‘Your exposition of the term beer-lahai-roi is quite correct, but there is more in it than you have said.’ He then began to discourse thus. ‘It is written: A fountain of gardens, a well of living waters, and flowing streams from Lebanon (S. S. IV, 1). “A fountain of gardens” is a description of Abraham; “a well of living waters” is a description of Isaac, of whom it is written: “And Isaac dwelt by the well of the living and seeing one (beer-lahai-roi).” The “well” is none other but the Shekinah; “the living one” is an allusion to the Righteous One who lives in the two worlds, that is, who lives above, in the higher world, and who also lives in the lower world, which exists and is illumined through him, just as the moon is only illumined when she looks at the sun. Thus the well of existence literally emanates from “the living one” whom “it sees”, and when it looks at him it is filled with living waters. (The word “living” is similarly used in the verse ”And Benaiah the son of Jehoiada, the son of a living man” (II Sam. XXIII, 20), i.e. a righteous man who illumines his generation as the living Deity above illumines the universe.) So the well constantly looks to the “living one” to be illumined. Further, the statement that Isaac dwelt by Beer-lahai-roi teaches the same lesson as the statement “And Isaac was forty years old when he took Rebekah” (Gen. XXV, 20), and abode with her and was united with her, symbolising in this way the union of darkness with night, as it is written: “His left hand under my head” (S. S. II, 6). Observe now that after Abraham's death Isaac remained in Kiriath-arba; how, then, it may be asked, can it say that he dwelt in Beer-lahai-roi? The answer is, to indicate that Isaac attached himself and held fast to that well in order to awaken the attribute of mercy, as already explained.’