Eusebius of Caesarea

You see here that he distinguishes two covenants, the old and the new, and says that the new would not be like the old which was given to the fathers. For the old covenant was given as a law to the Jews, when they had fallen from the religion of their forefathers, and had embraced the manners and life of the Egyptians, and had declined to the errors of polytheism and the idolatrous superstitions of the Gentiles. It was intended to raise up the fallen, and to set on their feet those who were lying on their faces, by suitable teaching. "For the law, it is said, is not for the righteous, but for the unjust and disorderly, for the unrighteous and sinners, and for those like them."