“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. For this Hagar is Mount Sinai in Arabia, and answers to Jerusalem, which now is, and is in bondage with her children. But Jerusalem which is above is free, which is the mother of us all. For it is written, Rejoice, thou barren that bearest not: break forth and cry, thou that travailest not: for the desolate hath many more children than she which hath an husband. Now we, brethren, as Isaac was, are the children of promise. But as then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now. Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the free woman. So then, brethren, we are not children of the bond-woman, but of the free” (Gal. 4:21-31).
The first covenant was faulty. It was faulty in the promises; because it rested primarily upon the promises of the people wherein the people promised something that it was impossible for them to do.
Why, then, were they allowed of the Lord to enter into such a covenant? Did he not know that the people could not do what they promised? —To be sure, he did.
But the people did not know it. “Living [in Egypt] in the midst of idolatry and corruption, they had no true conception of the holiness of God; of the exceeding sinfulness of their own hearts; their utter inability, in themselves, to render obedience to God’s law; and their need of a Saviour. ALL THIS THEY MUST BE TAUGHT. God brought them to Sinai; he manifested his glory; he gave them his law, with the promise of great blessings on condition of obedience . . .. The people did not realize the sinfulness of their own hearts, and that without Christ it was impossible for them to keep God’s law; and they readily entered into covenant with God. Feeling that they were able to establish their own righteousness, they declared, ‘All that the Lord hath said will we do, and be obedient.’”
Since the people did not know these essential things concerning themselves; —“their utter inability, etc.; --since they would not believe God, so that they could know; —and since “all this they must be taught,” —the only sure means by which they could be caused to learn this which they did not know was to have them try, and fail; and so learn by experience that they could not of themselves establish their own righteousness as the righteousness of God. Then they would be willing to accept by faith God’s righteousness, which is established by faith.