Cyprian of Carthage, Exhortation to Martyrdom, Addressed to Fortunatus Chapter 3: That God alone must be worshipped

“As it is written, Thou shalt worship the Lord thy God, and Him only shalt thou serve.” Also in Exodus: “Thou shalt have none other gods beside me.” Also in Deuteronomy: “See ye, see ye that I am He, and that there is no God beside me. I will kill, and will make alive; I will smite, and I will heal; and there is none who can deliver out of mine hands.” In the Apocalypse, moreover: “And I saw another angel fly in the midst of heaven, having the everlasting Gospel to preach over the earth, and over all nations, and tribes, and tongues, and peoples, saying with a loud voice, Fear God rather, and give glory to Him: for the hour of His judgment is come; and worship Him that made heaven and earth, and the sea, and all that therein is.” So also the Lord, in His Gospel, makes mention of the first and second commandment, saying, “Hear, O Israel, The Lord thy God is one God;” and, “Thou shalt love thy Lord with all thy heart, and with all thy soul, and with all thy strength. This is the first; and the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the law and the prophets.” And once more: “And this is life eternal, that they may know Thee, the only and true God, and Jesus Christ, whom Thou hast sent.”