Albert Barnes
As the sixth, seventh, and eighth commandments forbid us to injure our neighbor in deed, the ninth forbids us to injure him in word, and the tenth, in thought. No human eye can see the coveting heart; it is witnessed only by him who possesses it and by Him to whom all things are naked and open Luke 12:15-21. But it is the root of all sins of word or deed against our neighbor James 1:14-15.
Compare Deuteronomy 5:22-31. Aaron Exodus 19:24 on this occasion accompanied Moses in drawing near to the thick darkness.
Exodus 20:22 to Exodus 23:33 is a series of laws which we may identify with what was written by Moses in the book called the book of the covenant, and read by him in the audience of the people Exodus 24:7.
The document cannot be regarded as a strictly systematic whole. Portions of it were probably traditional rules handed down from the patriarchs, and retained by the Israelites in Egypt.
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).