“He who practices righteousness is righteous, just as He is righteous.” (1 John 3:7, NKJV) 

Just because everyone wears the same uniform does mean they are on the same team. A well-known enemy tactic is to infiltrate the ranks of the foe by trying to blend in with them. 

Earlier John spoke of those who were part of the fellowship who departed from it because they were not really of it (1 John 2:19). It turns out they were in league with the devil. They would well have said, “Lord, Lord,” but not actually done as Jesus commanded. If not sooner, then later on the day of judgment they would be exposed and hear the pronouncement of Jesus, “Be gone; I never knew you.” 

How do we know those who are children of God and those who are of their father, the devil? Later John will tell us we can know them by their doctrine (4:1-3), but here he points to their deeds. “He who practices righteousness is righteous, just as He is righteous. He who sins is of the devil, for the devil has sinned from the beginning” (3:7-8). 

Again, John holds up Jesus for us. He is righteous. He is the Righteous One. Those rooted in Him through faith will grow up in Him and so reflect His character through God’s handiwork of grace. As Christ is formed in us, so Christ will be seen through us. 

The telltale sign is whether our lives show evidence of obedience or disobedience, righteousness or wickedness, light or darkness, truth or error. Genuine union with Christ will manifest itself in our lives and bear witness to ourselves and others of the presence of Christ in us. When Jesus confronted the religious leaders of His day, He linked their character to their father and service to his kingdom (see John 8:39-47). 

John makes it clear that, “For this purpose the Son of God was manifested, that He might destroy the works of the devil” (1 John 3:8). Jesus gained that victory through His death and resurrection, commencing His Kingdom rule, and will one day consummate His Kingdom through the eradication of Satan’s kingdom and ushering in of the new creation. 

For now, though, we are to be discerning. John says, “Little children, let no one deceive you” (3:7). The sense is that we are to be discerning of the truth and grounded in Christ so that we will not be led astray. 

What does this mean for us? Two things. One, in regard to ourselves we must take stock of our own steps and inclinations of our heart. After all, John writes what he does to assure us of eternal life (5:13). Are we inclined to righteousness and obedience to our Lord Jesus? Is our heart grieved when we go astray? Two, in regard to those leaders, teachers, and influencers around us, are their words and ways in accord with what the Bible teaches? 

How does walking in righteousness relate to our Christianity?