How do we know that believers are children of God?

The assurance of being a child of God arises from the doctrine of adoption. Romans 8:15 tells us, 'For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father.' This adoption is not of our choosing but is a sovereign act of God's grace, whereby He chooses individuals to become His children. It affirms that believers are born of God, not by their own will or effort but through God's initiating love and action. Moreover, those who are led by the Spirit of God are recognized as His children, signifying a transformative relationship that reflects His character and attributes.