Thus the Creed's final "Amen" repeats and confirms its first words: "I believe." To believe is to say "Amen" to God's words, promises and commandments; to entrust oneself completely to him who is the "Amen" of infinite love and perfect faithfulness. The Christian's everyday life will then be the "Amen" to the "I believe" of our baptismal profession of faith:
May your Creed be for you as a mirror. Look at yourself in it, to see if you believe everything you say you believe. And rejoice in your faith each day.
Source: Catechism of the Catholic Church (Vatican.va)