Catechism Part 1, Section 2, Chapter 1, Article 1, Paragraph 1: I Believe in God (199-231)

This first affirmation, belief in God, is the most fundamental. The whole Creed speaks of God, and when it also speaks of man it does so in relation to God. All the other articles of the Creed depend on the first. Through the prophets God calls Israel and all nations to turn to him, the one and only God.
First of all, the Church asserts that there is only one God, but belief in Jesus and the Holy Spirit does not contradict this, for they are of the same essence.
Second, God made Himself known by revealing His divine name, "I AM WHO I AM," which is a mystery. By revealing his name, God also reveals his faithfulness. Man discovers his own insignificance in God's presence, but God can forgive those who realize they are a sinner. God is merciful, gracious, and faithful. God is unique, and there are no gods like Him. He transcends the world and history. He made heaven and earth. Through His name we learn that He IS who he is and does not change from everlasting to everlasting .
God is Truth itself, and can be trusted. His truth is wisdom, and His teaching is true instruction. God is also Love, and revealed Himself out of His love. His love is everlasting, and is like a father to his son. In addition, God's very being is love.
 The implications of faith in one God means coming to know God's greatness and Majesty by serving God first. Another implication of faith is living in thanksgiving because we have received all from him. A third implication means knowing the Unity and true dignity of all men. Fourthly it means making good use of created things faith in God, the only One, leads us to use everything that is not God only insofar as it brings us closer to him and to detach from it insofar as it brings us closer to him, and to detach ourselves from it insofar as it turns away from him. Fifthly it means trust in God in every circumstance, even in adversity.