First John 3:20 says, “If our hearts condemn us, we know that God is greater than our hearts, and he knows everything.” Here John reminds us that God is greater than our feelings of guilt, and He is greater than the mistakes we make when we sin.
Today, we often use the word heart to refer to the organ that pumps blood through the body. However, in the Bible the word heart usually refers to someone’s emotions or desires—the center of his will or his true self. This is true of both God and humanity. For example, God refers to King David as “a man after my own heart” (1 Samuel 13:14; Acts 13:22). In other words, David sought to do all that God had willed. In Mark 7:21–22, Jesus says that out of a person’s heart flow sinful and evil desires.
When John says that that God is greater than our hearts, he’s telling us that God is greater than our desires, emotions, and wills.
First John 3:20 begins with a conditional clause: If our hearts condemn us. This is a reference to the conviction and guilt a believer feels when he or she sins. Such a feeling is actually a sign of a mature and growing faith in a believer—it shows he is aware of his sin and continued need for God. But those who are in Christ can be assured of their salvation and the forgiveness they have received from God (Hebrews 10:22). In other words, they can trust that God is greater than the sins that flow out of their hearts.
First John 3:20 ends by reminding us that God “knows everything“—He is omniscient. He knows every action we take and every motive in our hearts. He knows our sin. He also knows what we’re thinking and feeling when we sin. Yet He wants us to know that He’s bigger and greater than all of that, and He wants us to rest in that truth.
So, when we feel convicted for our sins, 1 John 3:20 reminds us that God’s love is greater than that conviction. When a believer sins, he or she should not wallow in guilt or fear before God but rather ask for His forgiveness and rest in the truth that He is faithful to forgive (1 John 1:9). When a believer remembers his or her past sins, however awful they may be, he or she should not despair but trust that God is greater than our past. Hebrews 4:16 gives us this encouragement: “Let us then approach God’s throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.”