.
It is by being born again of water and the Holy Ghost, that is, by sacramental
Baptism, that one becomes a child of God.
Some say "we are all children of God," but that is only true inasmuch as we
are all CAPABLE of becoming children of God. That is, we are all potentially
children of God, but do not become so until we receive holy Baptism.
Baptism is necessary to remove original sin from the soul. One cannot be
absolved in Confession until one is first baptized, because absolution does
not remit original sin; only Baptism does that.