(Please read the passage cited above first.)
My sisters and brothers,
St John writes that all who believe that Jesus is the Christ are begotten by God. What does it mean to be begotten or born of God? We call Christ the only-begotten Son of the God. We are trying to say that Christ has the same nature equal to the Father’s. The Son of God has the same nature as God; he is not adopted.
All those who believe that Jesus is the Christ are begotten by God and have the same nature as God. In one sense we can speak of adoption (because we have human natures from our parents) but in another and real sense we are begotten by God because we have believed that Christ is the Son of God and through our baptism Christ has made himself one with us. We are the body of Christ. We share his divine nature as he shares our human nature.
How can I prove this? All those who love the Father and do God’s commandments are children begotten of God because they do exactly what God does. In our families, children look like their parents and act like their parents. The same goes with the children of God: they look like God and do the same things that God does.
The commandments of God are not a burden because we learn from God how to look like God and do the same things that God does. Children learn from their parents how to love others, and those who believe in Christ likewise learn how to love as God loves. The commandment is that we learn to love as God loves.
Why do we have the ability to obey this commandment? We do because we have conquered the world through our faith in Jesus the Son of God. Through our faith we have the power to keep the commandment. Our faith has conquered the world and the disobedience of the old nature.
Brothers and sisters, we have conquered the world through our baptism into faith in Christ, the only-begotten Son of God. Today we no longer wear the white baptismal clothing of those recently baptized. Instead we wear ordinary clothing. Our actions, not our clothing, now proclaims that we are begotten by God and have conquered the world.