"With Baptism we become children of God in His only-begotten Son, Jesus Christ. Rising from the waters of the baptismal font, every Christian hears again the voice that was once heard on the banks of the Jordan River: 'You are my beloved Son; with You I am well pleased' (Lk 3:22). From this comes the understanding that one has been brought into association with the beloved Son, becoming a child of adoption (cf. Gal 4:4-7) and a brother or sister of Christ. In this way the eternal plan of the Father for each person is realized in history: 'For those whom He foreknew He also predestined to be conformed to the image of His Son, in order that He might be the firstborn among many brethren' (Rom 8:29)."
-John Paul II in the Apostolic Exhortation Christifideles Laici.