In John 1:12 (NIV) the Apostle John says, “Yet to all who did receive him, to those who believed in his name, he gave the right to become children of God.” Therefore all who receive Jesus Christ and believe in his name, the right to become a child of God is given to you by Jesus Christ, the Son of God and Savior of the world.
In Romans 8:14 (NIV) the Apostle Paul says, “For those who are led by the Spirit of God are the children of God.” Therefore when we receive Jesus Christ, his Holy Spirit comes to dwell in us and we are led by his Spirit. Our lives should reflect this by evidences of the Fruit of the Spirit mentioned in Galatians 5:22-23.
If we don’t have any of these nine fruits of God’s Holy Spirit evident in our lives, are we really children of God? These nine fruits of the Spirit listed in Galatians are how people will know we are Christians (children of God). The Apostle Paul says in Galatians 5:22-23, “But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, gentleness and self-control. Against such things there is no law.”
So if we believe in Jesus Christ as our Savior and Lord and receive his Holy Spirit how will we really know we are children of God?
The Apostle Paul says further in Romans chapter 8:15-17 that, “The Spirit you received does not make you slaves, so that you live in fear again; rather, the Spirit you received brought about your adoption to sonship. And by him we cry, “Abba, Father.” The Spirit himself testifies with our spirit that we are God’s children. Now if we are children, then we are heirs—heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory.”
Does God’s Holy Spirit testify with your spirit that you are His child? If not, today is the day of salvation!
For additional study on "children of God," here are additional scripture in the Bible that speaks about children of God: Luke 20:36 John 1:12 John 1:13 John 8:41 John 11:52 Romans 8:14 Romans 8:17
Romans 8:19 Romans 8:21 Romans 9:8 Romans 9:26 Galatians 3:23 Galatians 3:26 Philippians 2:15 1 John 3:1
1 John 3:2 1 John 3:10 1 John 5:2 1 John 5:19 Hebrews 12:4-13
Note: The term "children of God" is only listed in the New Testament. I did not find any scripture in the Old Testament that talks about "children of God." The OT refers to children of Israel or God's chosen people, but not children of God.