Since many preachers’ definitions of heart do not include any scriptures, I have to believe they get that from psychology or at least some commentary. That bothers me. My first red flag popped up when one man said the heart is the emotional center. That would be a physical heart if I understand correctly. We ponder, think, and understand, etc. with the spiritual heart but not with the physical. A quick reference list shows that certain qualities (good or bad) are in the heart (Matt. 15:16-19). I am not sure how murder fits in, but it is a quality too. Look carefully at the Hebrew meaning of Prov. 23:7–as a man thinketh in his heart. That is strange, but necessary to understand.