But as many as received Him, to them He gave the right to become children of God, even to those who believe in His name… John 1:12
Blessed be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in the heavenly places in Christ, just as He chose us in Him before the foundation of the world, that we would be holy and blameless before Him. In love He predestined us to adoption as sons through Jesus Christ to Himself, according to the kind intention of His will, to the praise of the glory of His grace, which He freely bestowed on us in the Beloved. In Him we have redemption through His blood, the forgiveness of our trespasses, according to the riches of His grace which He lavished on us…
Ephesians 1:3-8
The Spirit Himself testifies with our spirit that we are children of God, and if children, heirs also, heirs of God and fellow heirs with Christ… Romans 8:16-17
Blessed be the God and Father of our Lord Jesus Christ, the Father of mercies and God of all comfort, who comforts us in all our affliction so that we will be able to comfort those who are in any affliction with the comfort with which we ourselves are comforted by God. 2 Corinthians 1:3~4
So Paul stood … and said, “… I observe that you are very religious in all respects. For while I was passing through and examining the objects of your worship, I also found an altar with this inscription, ‘TO AN UNKNOWN GOD.’ Therefore what you worship in ignorance, this I proclaim to you. The God who made the world and all things in it, since He is Lord of heaven and earth, does not dwell in temples made with hands; nor is He served by human hands, as though He needed anything, since He Himself gives to all people life and breath and all things; and He made from one man every nation of mankind to live on all the face of the earth, having determined their appointed times and the boundaries of their habitation, that they would seek God, if perhaps they might grope for Him and find Him, though He is not far from each one of us; for in Him we live and move and exist, as even some of your own poets have said, ‘For we also are His children.’ Being then the children of God, we ought not to think that the Divine Nature is like gold or silver or stone, an image formed by the art and thought of man. Therefore having overlooked the times of ignorance, God is now declaring to men that all people everywhere should repent, because He has fixed a day in which He will judge the world in righteousness through a Man whom He has appointed, having furnished proof to all men by raising Him from the dead.” Acts 17:22-31
Blessed be the God and Father of our Lord Jesus Christ, who according to His great mercy has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead, to obtain an inheritance which is imperishable and undefiled and will not fade away, reserved in heaven for you, who are protected by the power of God through faith for a salvation ready to be revealed in the last time. In this you greatly rejoice, even though now for a little while, if necessary, you have been distressed by various trials… 1 Peter 1:3~6
See how great a love the Father has bestowed on us, that we would be called children of God; and such we are. 1 John 3:1