"Heart" in our opening scripture doesn't refer to the organ in your body that pumps blood. It refers to your spirit, which is the real you. Man is a spirit and has a soul. He's able to reason because he has a soul, and able to believe because he is a spirit. The body contacts the soul through the five human senses of sight, sound, smell, taste and touch. The soul, through the mind, gives intellectual interpretation to the messages or signals from these senses. In brief, what the brain is to the body, the mind is to the soul. The soul, through the mind, also gives intellectual interpretation to messages received from the human spirit. However, man contacts God through his spirit and not with the mind or his senses. Only the spirit can accept spiritual realities, and has the capacity to believe. The human spirit isn't limited by the human senses like the soul, which argues and often rejects what it doesn't understand. Thank God, that believing is with the spirit. The Word of God is meant for your spirit. If the Word can get into your spirit, even when your mind doesn't understand it, you'll surely believe. Once you believe, the next necessary action would be to speak. Your believing comes ahead of your confessions of faith. David said, "I believed, therefore have I spoken…" (Psalm 116:10). He didn't say, "I spoke, trying to believe." Your faith works from inside out; though you believe with the heart, it's with the mouth that confession is made unto salvation. The Word gets into your heart through your mind, because your mind is the door to your human spirit. When you hear the Word, accept it with your spirit and it'll become a life-force that causes you to live accordingly.