Exodus 20:22

I have talked with you from heaven - Though God manifested himself by the fire, the lightning, the earthquake, the thick darkness, etc., yet the ten words, or commandments were probably uttered from the higher regions of the air, which would be an additional proof to the people that there was no imposture in this case; for though strange appearances and voices might be counterfeited on earth, as was often, no doubt, done by the magicians of Egypt; yet it would be utterly impossible to represent a voice, in a long continued series of instruction, as proceeding from heaven itself, or the higher regions of the atmosphere. This, with the earthquake and repeated thunders, (see on Exodus 20:18 (note)), would put the reality of this whole procedure beyond all doubt; and this enabled Moses, Deuteronomy 5:26, to make such an appeal to the people on a fact incontrovertible and of infinite importance, that God had indeed talked with them face to face.

Nothing could be more appropriate as the commencement of the book of the covenant than these regulations for public worship. The rules for the building of altars must have been old and accepted, and are not inconsistent with the directions for the construction of the altar of the court of the tabernacle, Exodus 27:1-8 (compare Joshua 22:26-28).

20:22 Moses being gone into the thick darkness where God was, God there spoke in his hearing only, all that follows from hence to the end of chap. 23, which is mostly an exposition of the ten commandments; and he was to transmit it to the people. The laws in these verses relate to God's worship.

Ye have seen that I have talked with you from heaven — Such was his wonderful condescension; ye shall not make gods of silver - This repetition of the second commandment comes in here, because they were more addicted to idolatry than to any other sin.