We become children of God by faith in Jesus Christ but not apart from putting on Christ in baptism. The two are inseparably connected in scripture: “For ye are all the children of God by faith in Christ Jesus. For as many of you as have been baptized into Christ have put on Christ”
We must never think of baptism as a mere sign or symbol but rather as the divinely appointed ordinance in which we “put on Christ” (Galatians 3:27). Just as we clothe ourselves in appropriate garments for protection from the elements, even so in Christian baptism we are clothed with Jesus Christ and thereby become partakers of his salvation.
All who “have been baptized into Christ have put on Christ” and are “children of God by faith in Jesus Christ” thereby becoming partakers of all the benefits that are found in him.