Romans 8:14-17

8:14 For all who are led by the Spirit of God are the sons of God. 8:15 For you did not receive the spirit of slavery leading again to fear, but you received the Spirit of adoption, by whom we cry, “Abba, Father.” 8:16 The Spirit himself bears witness to our spirit that we are God’s children. 8:17 And if children, then heirs (namely, heirs of God and also fellow heirs with Christ) – if indeed we suffer with him so we may also be glorified with him.

Romans 8:29

8:29 because those whom he foreknew he also predestined to be conformed to the image of his Son, that his Son would be the firstborn among many brothers and sisters.