37. A Christian vocation
When studying the Commandments, the Catechism of the Catholic Church refers to the study of Christian doctrine with an evocative title: “Life in Christ”. This is the explanation of the Symbol of faith (first part), where reasons of God's gifts to man during the creation are given. There are also reasons for redemption, another gift from God to men. The development of the teaching about the sacraments (second part) illustrates how grace is given at the celebration of the mystery of Christ; we are part of the divine nature and sons of God thanks to the baptism. With the baptism we start a new life, the life in Christ. But a life in Christ needs the fullfilment of the commandments (third part), which means to be coherent with our faith and vocation, as St. Leo the Great wrote:
""Christian, recognize your dignity and, now that you share in God's own nature, do not return to your former base condition by sinning. Remember who is your head and of whose body you are a member. Never forget that you have been rescued from the power of darkness and brought into the light of the Kingdom of God."(Sermón 21).