Exodus 23:20
19 The first of the firstfruits of your soil you must bring to the house of the Lord your God. “You must not cook a young goat in its mother’s milk. 20 “I am going to send a messenger before you to protect you as you journey and to bring you into the place that I have prepared. 21 Take heed because of him, and obey his voice; do not rebel against him, for he will not pardon your transgressions, for my Name is in him.
Onkelos Exodus 23:20
19 The beginning of the first fruits of your land you will bring into the sanctuary of the Lord God. Do not eat meat with milk. 20 Behold, I send My Angel before you, to protect you in the way, and to bring you into the place which I have prepared. 21 Take heed before Him, and hearken to His words; rebel not against Him, for He will not forgive your sins; for in My Name are His words.
Notes and References
"... Based on Exodus Rabbah (32:3), Rashi suggests the untenable idea that God informed the Israelites that He would not accompany them since they will ultimately sin, as indicated in 33:3. Instead, not abandoning them completely, He would send an angel (messenger) in His stead to lead them. Ibn Ezra identifies the angel as Michael. Nachmanides disagrees and suggests that the angel mentioned is the 'Redeeming Angel' referred to in Genesis 48:16, meaning God Himself ..."
Drazin, Israel, and Stanley M. Wagner Onkelos on the Torah, Exodus: Understanding the Bible Text (p. 155) Gefen, 2006