Can a person really know that he or she is a child in God’s family? Of course! The First Epistle of John was written to assure believers that they are the children of God (1 John 5:11–13). Seven times in this letter, the Apostle John uses the phrase “born of God.” If you put these statements together, you discover four “birthmarks” of the true believer:
• practicing righteousness and not sin (2:29; 3:9)
• loving God and other believers (4:7; 5:1)
• overcoming the world (5:4)
• overcoming the devil (5:18)
John was not suggesting that God’s children never sin. The tense of the verbs in 2:29 and 3:9 literally means “everyone that practices righteousness” and “does not practice sin.” God does not want his children to sin at all (1 John 2:1); but if they do sin, he has made provision for their cleansing (1 John 1:9). Christians are not people who are sinless, but who do sin less. The “bent” of their life is toward godliness and obedience.
Along with these “birthmarks,” the believer has the witness of God’s Word (1 John 5:9–13) and the witness of God’s Spirit (Rom. 8:9, 14–17). These two witnesses are like “spiritual birth certificates” that assure us we are God’s own children.
Warren W. Wiersbe, Be What You Are: 12 Intriguing Pictures of the Christian from the New Testament (Wheaton, IL: Tyndale House, 1988), 13–14.