Tertullian — On Baptism 2

But not yet about the good to be got from martyrdom must we learn, without our having first heard about the duty of suffering it; nor must we learn the usefulness of it, before we have heard about the necessity for it. The (question of the) divine warrant goes first — whether God has willed and also commanded ought of the kind, so that they who assert that it is not good are not plied with arguments for thinking it profitable save when they have been subdued. It is proper that heretics be driven to duty, not enticed. Obstinacy must be conquered, not coaxed. And, certainly, that will be pronounced beforehand quite good enough, which will be shown to have been instituted and also enjoined by God .

Let the Gospels wait a little, while I set forth their root the Law, while I ascertain the will of God from those writings from which I recall to mind Himself also: I am, says He, God , your God , who have brought you out of the land of Egypt . You shall have no other gods besides me. You shall not make unto you a likeness of those things which are in heaven, and which are in the earth beneath, and which are in the sea under the earth. You shall not worship them, nor serve them. For I am the Lord your God. Exodus 20:2 Likewise in the same book of Exodus: You yourselves have seen that I have talked with you from heaven. You shall not make unto you gods of silver, neither shall you make unto you gods of gold.

Exodus 20:22-23 To the following effect also, in Deuteronomy: Hear, O Israel ; The Lord your God is one: and you shall love the Lord your God with all your heart and all your might, and with all your soul . Deuteronomy 6:4 And again: Neither do you forget the Lord your God , who brought you forth from the land of Egypt , out of the house of bondage. You shall fear the Lord your God , and serve Him only, and cleave to Him, and swear by His name. You shall not go after strange gods, and the gods of the nations which are round about you, because the Lord your God is also a jealous God among you, and lest His anger should be kindled against you, and destroy you from off the face of the earth.

Deuteronomy 6:12 But setting before them blessings and curses, He also says: Blessings shall be yours, if you obey the commandments of the Lord your God , whatsoever I command you this day, and do not wander from the way which I have commanded you, to go and serve other gods whom you know not. Deuteronomy 11:27 And as to rooting them out in every way: You shall utterly destroy all the places wherein the nations , which you shall possess by inheritance, served their gods, upon mountains and hills, and under shady trees. You shall overthrow all their altars, you shall overturn and break in pieces their pillars, and cut down their groves, and burn with fire the graven images of the gods themselves, and destroy the names of them out of that place.