I see that God shows no partiality. Rather, in every nation whoever fears him and acts uprightly is acceptable to him”
(Acts 10:34-35)
Through Baptism we are freed from sin and regenerated as children of God, we become members of Christ and we are incorporated into the Church and made partakers of its mission," states the Catechism of the Catholic Church (CCC 1213).
Baptize means "to submerge" or "to enter into the water". This immersion symbolizes the act of burying the person in the death of Christ (when the water is poured), from where he comes out by resurrection with Him (when he is dried from the water). Christian baptism has its beginnings since the time of the Apostles.
Generally, the one who baptizes is the priest but, if necessary, any person, even not baptized, can baptize (cf. CIC can. 861, § 2) if he has the required intention and uses the Trinitarian baptismal formula. Baptism imprints in the Christian an indelible spiritual seal of his belonging to Christ. This seal is not erased for any sin. Given once and for all, that is, Baptism is received only once in a lifetime.