Just as Jesus began his ministry through baptism, our own baptism is the first step in a life-long commitment to Discipleship. We are baptized as children into God's community and baptized as adults when we consciously accept the Holy Trinity of Father, Son and Holy Spirit into our hearts to become heirs of heaven. We put on our white garment of 'immortality' to join with Christ. With the sign of the Cross, we declare our intent to leave sin and separation behind, which seals and consecrates our commitment.

As we are baptized in the water and the Spirit, and/or with the laying on of hands, we are 'anointed' and joined with Christ in the fullness of the Eucharistic celebration and are fully welcomed into the Body of Christ and the Church community with the prayer of 'Our Father...'

1218 Since the beginning of the world, water, so humble and wonderful a creature, has been the source of life and fruitfulness. Sacred Scripture sees it as "overshadowed" by the Spirit of God. (12) At the very dawn of creation Your spirit breathed on the waters, making them the wellspring of all holiness. (13) http://www.vatican.va/archive/ccc_css/archive/catechism/p2s2c1a1.htm
From the Catechism of the Catholic Church