1 Corinthians 10:1-4 "Moreover, brethren, I do not want you to be unaware that all our fathers were under the cloud, all passed through the sea, all were baptized into Moses in the cloud and in the sea, all ate the same spiritual food, and all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ." NKJV
"But in what sense was the rock Christ? Not that Christ appeared under the form of a rock; nor that the rock was a type of Christ, for that does not suit the connection. The idea is not that they drank of the typical rock; it was not the type but the anti-type that supplied their wants. The expression is simply figurative. Christ was the rock in the same sense that he is the vine. He was the source of all the support which the Israelites enjoyed during their journey in the wilderness.
This passage distinctly asserts not only the preëxistence of our Lord, but also that he was the Jehovah of the Old Testament. He who appeared to Moses and announced himself as Jehovah, the God of Abraham, who commissioned him to go to Pharaoh, who delivered the people out of Egypt, who appeared on Horeb, who led the people through the wilderness, who dwelt in the temple, who manifested himself to Isaiah, who was to appear personally in the fullness of time, is the person who was born of a virgin, and manifested himself in the flesh."
A Commentary on 1&2 Corinthians. Charles Hodge. The Banner of Truth Trust, 3 Murrayfield Road, Edinburgh EH12 6EL & P.O. Box 652, Carlisle, PA 17013. Page 175.