1 John 4:20 - 5:1
20 If someone says, “I love God,” and hates his brother, he is a liar; for the one who does not love his brother whom he has seen, cannot love God whom he has not seen. 21 And this commandment we have from Him, that the one who loves God should love his brother also. Overcoming the World
Everyone who believes that Jesus is the Christ has been born of God, and everyone who loves the One who gives new birth loves also the one who has been born of Him.