I finally understood this scripture:
1 John 2:4-6 (The Message)
If someone claims, "I know him well!" but doesn't keep his commandments, he's obviously a liar. His life doesn't match his words. But the one who keeps God's word is the person in whom we see God's mature love. This is the only way to be sure we're in God. Anyone who claims to be intimate with God ought to live the same kind of life Jesus lived.
1 John 2:4 (New King James Version)
He who says, “I know Him,” and does not keep His commandments, is a liar, and the truth is not in him.