Two Testaments, One Religion

The Old Testament and the New contain not two different religions, but one in different stages of development. Well did Augustine say: "In the Old Testament the New lies hidden; in the New Testament the Old lies open." The essential principal of Judaism and of Christianity is the same supreme love to God. The Great Teacher and Law-giver sums up the law, and the prophets, and all human duty in this great word LOVE. It is the natural and necessary inference from the unity of God, as opposed to polytheism; hence it follows the "Shema," the first words every Hebrew child is taught to speak, "Hear, O Israel, the Lord our God is one Lord; and thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy might" (Deut. vi. 4, 5).

— from Mile-Stone Papers Part 1, Chapter 5.