Only those who are believers and are living by God’s spirit are children of God and are joint heirs of the kingdom along with Jesus. It is they who will inherit the blessings that God promises and they who will share in Jesus’ glory, but they will also share in his persecution and suffering (John 1:10-13, 1 John 3:9-10, Rom 8:7-17).
All NLT translations:
John 1:10 He [Jesus] came into the very world he created, but the world didn’t recognize him. 11 He came to his own people, and even they rejected him. 12 But to all who believed him and accepted him, he gave the right to become children of God. 13 They are reborn—not with a physical birth resulting from human passion or plan, but a birth that comes from God.
1 John 3:9-10 Those who have been born into God’s family do not make a practice of sinning, because God’s life is in them. So they can’t keep on sinning, because they are children of God. So now we can tell who are children of God and who are children of the devil. Anyone who does not live righteously and does not love other believers does not belong to God.
Romans 8:7 For the sinful nature is always hostile to God. It never did obey God’s laws, and it never will. 8 That’s why those who are still under the control of their sinful nature can never please God. 9 But you are not controlled by your sinful nature. You are controlled by the Spirit if you have the Spirit of God living in you. (And remember that those who do not have the Spirit of Christ living in them do not belong to him at all.) 10 And Christ lives within you, so even though your body will die because of sin, the Spirit gives you life because you have been made right with God. 11 The Spirit of God, who raised Jesus from the dead, lives in you. And just as God raised Christ Jesus from the dead, he will give life to your mortal bodies by this same Spirit living within you. 12 Therefore, dear brothers and sisters, you have no obligation to do what your sinful nature urges you to do. 13 For if you live by its dictates, you will die. But if through the power of the Spirit you put to death the deeds of your sinful nature, you will live. 14 For all who are led by the Spirit of God are children of God. 15 So you have not received a spirit that makes you fearful slaves. Instead, you received God’s Spirit when he adopted you as his own children. Now we call him, “Abba, Father.” 16 For his Spirit joins with our spirit to affirm that we are God’s children. 17 And since we are his children, we are his heirs. In fact, together with Christ, we are heirs of God’s glory. But if we are to share his glory, we must also share his suffering.