Deuteronomy 17:2

In transgressing his covenant That is, in idolatry, as it is explained Deuteronomy 17:3, which is called a transgression of God's covenant made with Israel, both because it was a breach of their faith given to God, and of that law which they covenanted to keep; and because it was a dissolution of that matrimonial covenant with God, a renouncing of God and his worship, and a choosing other gods.