“Tell me, ye that desire to be under the law, do ye not hear the law? For it is written, that Abraham had two sons, the one by a bondmaid, the other by a free woman. But he who was of the bondwoman was born after the flesh; but he of the free woman was by promise. Which things are an allegory: for these are the two covenants: the one from the Mount Sinai, which genders to bondage, which is Hagar” (Gal. 4:21-24).
The covenant from Mount Sinai is the covenant that God made with the children of Israel when he took them by the hand to lead them out of Egypt.
That covenant was faulty. “For if that first covenant had been faultless, then should no place have been sought for the second” (Heb. 8:7).
That covenant was faulty in the promises: for the second covenant is “a better covenant” than that, in that it “was established upon better promises” (Heb. 8:6).
The fault in that covenant was primarily, in the people. “For finding fault with them, he saith, Behold the days come, saith the Lord when I will make a new covenant” (Heb. 8:8).
Therefore, since the fault of that covenant was in its promises, and the fault was primarily in the people themselves, it follows that the promises upon which that covenant was established were primarily the promises of the people.
What, then, were these promises? —They are in the covenant, which was made with them when they came forth out of Egypt, and here is that covenant: —
“Ye have seen what I did unto the Egyptians, and how I bare you on eagles’ wings, and brought you unto myself. Now therefore, if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people: for all the earth is mine: and ye shall be unto me a kingdom of priests, and an holy nation.” “And all the people answered together, and said, All that the Lord hath spoken we will do” (Ex. 19:4-6, 8).
In this agreement, all the people promised to obey the voice of the Lord. They had not yet heard what that voice would speak. But in the twentieth chapter, they heard that voice speaking the words of the Ten Commandments, to which, when the Lord had spoken, “he added no more.” And when they had heard this, they solemnly renewed their promise: “All that the Lord hath said will we do and be obedient.”
That this is the covenant that the Lord made with them when he took them by the hand to bring them out of Egypt, is made certain by the following words: —