Within chapter 12, Calvin asserts how the Scripture show that God alone is to be worshiped. God tells us from his word that he is a jealous God and hence “will be a stern avenger if he is confounded with any false god; and thereafter defines what due worship is, in order that the human race may be kept in obedience”. He uses the Law to bind his people to worship only him and as Calvin says, “it is designed as a bridle to curb men, and prevent them from turning aside to spurious worship”. If there are many gods alongside of God, the glory of the Godhead described in Scripture would be lessened and hence God’s Sovereign nature would also be lessened.

Calvin also deals with the ideas of dulia and latria since it was a common doctrine during his day. Dulia, according to the Catholic Encyclopedia, is the practice of giving honor and worship to saints while latria is the worship given to God alone. Calvin asserts that although Catholics make a distinction between the two modes of worship, they were really are the same thing. Christ himself deals with this in Matthew 4 when he says, “You shall worship the Lord your God and him only shall you serve.” Again in Revelations, when John falls down before the angel, the angel rebukes him for doing this. Men may be “worshipped” but Calvin asserts that this is only civil honor and religious worship. There are many other instances where the apostles rebuke others for bowing down to them and turn their attentions to God. Calvin ends the brief chapter with this statement: “Let it suffice to remember, that whatever offices of piety are bestowed anywhere else than on God alone, are of the nature of sacrilege. It is with this chapter that Calvin concludes his discourse on idols.