§2087
Morals › … › I. "You Shall Worship the Lord Your God and Him Only Shall You Serve"
Faith
Our moral life has its source in faith in God who reveals his love to us. St. Paul speaks of the "obedience of faith" as our first obligation. He shows that "ignorance of God" is the principle and explanation of all moral deviations. Our duty toward God is to believe in him and to bear witness to him.
Source: Catechism of the Catholic Church (Vatican.va)