Charles Ellicott Commentary Exodus 20:22

"And Jehovah said unto Moses, Thus thou shalt say unto the children of Israel, Ye yourselves have seen that I have talked with you from heaven." — Exodus 20:22 (ASV)

LAWS CONCERNING RELIGION.

Ye have seen that I have talked with you from heaven. —It was important to identify the giver of the Book of the Covenant with the deliverer of the Ten Commandments, and accordingly this was done in the opening words of the Book.