Charles Ellicott Commentary Exodus 23:20

"Behold, I send an angel before thee, to keep thee by the way, and to bring thee into the place which I have prepared." — Exodus 23:20 (ASV)

I send an Angel before you. —Kalisch considers Moses to have been the “angel” or “messenger;” others understand one of the created angelic host. But most commentators see in the promise the first mention of the “Angel of the Covenant,” who is reasonably identified with the Second Person of the Holy Trinity, the Eternal Son and Word of God. When the promise is retracted on account of the sin of the golden calf, it is in the words, I will not go up with you (Exodus 33:3).