20:1,2 God speaks many ways to the children of men; by conscience, by providences, by his voice, to all which we ought carefully to attend; but he never spake at any time so as he spake the TEN COMMANDMENTS. This law God had given to man before; it was written in his heart; but sin so defaced it, that it was necessary to revive the knowledge of it. The law is spiritual, and takes knowledge of the secret thoughts, desires, and dispositions of the heart. Its grand demand is love, without which outward obedience is mere hypocrisy. It requires perfect, unfailing, constant obedience; no law in the world admits disobedience to itself. Whosoever shall keep the whole law, and yet offend in one point, he is guilty of all, Jas 2:10. Whether in the heart or the conduct, in thought, word, or deed, to omit or to vary any thing, is sin, and the wages of sin is death.

2. I am the Lord thy God—This is a preface to the ten commandments—the latter clause being specially applicable to the case of the Israelites, while the former brings it home to all mankind; showing that the reasonableness of the law is founded in their eternal relation as creatures to their Creator, and their mutual relations to each other.