In the Bible, the ‘heart’ of a person is a barometer of their spiritual condition, the focal point of a person’s very being. In no way should we seek to understand the word ‘heart’ to just mean a muscle between our lungs that circulates our blood. Rather, the most common usage of ‘heart’ in Scripture is to describe man’s inclinations and personal will that we have in making decisions. The heart of man is the rational will coupled with the emotional desire.
What Scripture says about the heart of man
A brief survey of Scripture shows us that God truly looks at the heart (1 Samuel 16:7) to determine a person’s obedience to God, receptivity to God, and love for God. God knows the heart and all thoughts of the heart will be laid bare (Acts 15:8). What a joy to know that it is in our heart that music can be made (Colossians 3:16)! How often do we see the phrase in the Old Testament, “with all your heart” (see the Great Commandment in Deuteronomy 6:5, Matthew 22:37) to speak of an undivided devotion to God? Jesus tells His disciples that bad things cannot go into a man, but rather bad things come out of the heart of man (Matthew 12:34, 15:19).
The fall of the heart
The heart of man is naturally inclined toward sin. Because of the fall, “the heart is deceitful above all things” (Jeremiah 17:9). The heart is what determines whether a person will follow God or reject God (see Moses’ encounter with Pharaoh in Exodus 4-14 and Joshua’s command to the Israelites in Joshua 24:23). The heart can be hard as stone, or soft and tender to God’s instruction, warnings, and love (see Ezekiel 36:26). God can create in us a “pure heart” (Psalm 51:9-10) that is washed clean by His Spirit. Ultimately, the greatest event in a person’s life occurs in the heart when a person believes that Jesus is Lord and that God rose Him from the dead (Romans 10:8-9).
Body and soul
Scripture speaks of man as having a body and a soul. The body is the organic physical and material construction of man. The soul is comprised of the mind, heart, spirit, and will (these terms are often used interchangeably). The soul is the part of the human construction that is immaterial, yet most reflective of our created purpose to be God’s image bearers. So we rightly say, echoing 1 Samuel 16:7, that God does not judge us base on our looks, nor strength, or capabilities. He rather searches, knows, and changes the heart.
Trust in the Lord
“Trust in the Lord with all your heart, and do not lean on your own understanding. In all your ways acknowledge Him, and He will make your paths straight” (Proverbs 3:5-6). “Search me, O God, and know my heart! Try me and know my thoughts! And see if there be any grievous way in me, and lead me in the way everlasting” (Psalm 139:23-24).