1 John 3:19 This then is how we know that we belong to the truth, and how we set our hearts at rest in his presence whenever our hearts condemn us. For God is greater than our hearts, and he knows everything.
College Press NIV Commentary: Our love helps us to know whether we belong to the truth. John tells us that when we know that our hearts condemn us, our love is insufficient. Since God is greater than our hearts, then he can know who we are and what we are. Let us not try to deceive God by having only a “love with words or tongue.” God knows our hearts. We can set our hearts at rest in his presence if we are obedient to his command. We know that we “belong to the truth” when our consciences are at ease in his presence.