Romans 8:14-17
14 For all who are led by the Spirit of God are sons of God. 15 For you did not receive the spirit of slavery to fall back into fear, but you have received the Spirit of adoption as sons, by whom we cry, “Abba! Father!” 16 The Spirit himself bears witness with our spirit that we are children of God, 17 and if children, then heirs—heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him.
1 John 3:1
3:1 See what kind of love the Father has given to us, that we should be called children of God; and so we are. The reason why the world does not know us is that it did not know him.
Mark 10:15
15 Truly, I say to you, whoever does not receive the kingdom of God like a child shall not enter it.”
Matthew 7:9-11
9 Or which one of you, if his son asks him for bread, will give him a stone? 10 Or if he asks for a fish, will give him a serpent? 11 If you then, who are evil, know how to give good gifts to your children, how much more will your Father who is in heaven give good things to those who ask him! (ESV)