This argument is still further strengthened by the fact, that the spirit and essential requirements of Judaism and Christianity are identical. It has indeed been asserted that the morality of the Old Testament was one of legal enactment; whereas that of the New Testament is one of motives and principles. But our Lord teaches a very different doctrine. He tells us that love was the essence and sum of all the requirements of the Old Testament, even as love is the fulfilling of the law under the present dispensation. {27} Christianity presents a new and powerful motive for obedience—namely gratitude for the incarnation and death of the Son of God; but this neither changes the nature of man’s moral obligation, nor removes the necessity of a positive enactment to guide him in his obedience, and enforce conformity to God’s will. If then in spirit and essence the moral requirements of the law and of the gospel were the same, what reason should there be for setting aside the decalogue, and what authority have we to ignore it without an express command from God? The probability that the moral law remains in force under the present dispensation, is still further strengthened by the use which is made of it by the inspired writers of the New Testament. St. Paul indeed speaks of the law as the “ministry of condemnation,” in opposition to the gospel, which is the “ministry of righteousness,” or justification—the one dispensation bearing on its front the justice of God, the other, his mercy.