Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
ONKELOS the Proselyte, who was thoroughly acquainted with the Hebrew and Chaldaic languages, made it his task to oppose the belief in God's corporeality. Accordingly, any expression employed in the Pentateuch in reference to God, and in any way implying corporeality, he paraphrases in
consonance with the context. All expressions denoting any mode of motion, are explained by Him to mean the appearance or manifestation of a certain light that had been created [for the occasion], i.e., the Shekhinah (Divine Presence), or Providence. Thus he paraphrases "the Lord will come down" (Exod. xix. 11), "The Lord will manifest Himself"; "And God came down" (xvi. 20), "And God manifested Himself"; and does not say "And God came down"; "I will go down now and see" (Gen. xviii. 21), he paraphrases, "I will manifest myself now and see." This is his rendering [of the verb yarad, "he went down," when used in reference to God] throughout his version, with the exception of the following passage, "I will go down (ered) with thee into Egypt" (Gen. xlvi. 4), which he renders literally. A remarkable proof of this great man's talents, the excellence of his version, and the correctness of his interpretation! By this version he discloses to us an important principle as regards prophecy.
This narrative begins: "And God spake unto Israel in the visions of the night, and said, Jacob, Jacob, etc. And He said, I am God, etc., I will go down with thee into Egypt" (Gen. xlvi. 2, 3). Seeing that the whole narrative is introduced as a vision of the night, Onkelos did not hesitate to translate literally the words addressed to Jacob in the nocturnal vision, and thus gave a faithful account of the occurrence. For the passage in question contains a statement of what Jacob was told, not what actually took place, as is the case in the words, "And the Lord came down upon Mount Sinai" (Exod. xix. 20). Here we have an account of what actually occurred in the physical world; the verb yarad is therefore paraphrased "He manifested Himself," and entirely detached from the idea of motion. Accounts of what happened in the imagination of man, I mean of what he was told, are not altered. A most remarkable distinction!
Hence you may infer that there is a great difference between a communication, designated as having been made in a dream, or a vision of the night, and a vision or a manifestation simply introduced with phrases like "And the word of the Lord came unto me, saying"; "And the Lord spake unto me, saying."
According to my opinion, it is also possible that Onkelos understood Elohim in the above passage to signify "angel," and that for this reason he did not hesitate to translate literally, "I will go down with thee to Egypt." Do not think it strange that Onkelos should have believed the Elohim, who said to Jacob, "I am God, the God of thy father" (ib. 3), to be an angel, for this sentence can, in the same form, also have been spoken by an angel. Thus Jacob says, "And the angel of God spake unto me in a dream, saying, Jacob. And I said, Here am I," etc. (Gen. xxxi. 11); and concludes the report of the angel's words to him in the following way, "I am the God of Bethel, where thou anointedst the pillar, and where thou vowedst a vow unto me" (ib. 13), although there is no doubt that Jacob vowed to God, not to the angel. It is the usual practice of prophets to relate words addressed to them by an angel in the name of God, as though God Himself had spoken to them. Such passages are all to be explained by supplying the nomen regens, and by considering them as identical with "I am the messenger of the God of thy father," "I am the messenger of God who appeared to thee in Bethel," and the like. Prophecy with its various degrees, and the nature of angels, will be fully
discussed in the sequel, in accordance with the object of this treatise (II. chap. xiv.).