This is addressed to Christians and others - Do you realise that the sins of the heart/spirit are the worst.?
It was sin of the heart that killed Jesus - mostly jealousy and the fear in the men of power of losing their position. Pride and rivalry were the sins in the religious leaders that angered Jesus so much. Un-forgiveness boastfulness, arrogance, a holier -than -thou attitude, a critical, abusive spirit- all these are sins of the heart.
Jesus readily forgave those whose sin was of the flesh, (of the body) immoral women for example. A man keen on money, Zacchaeus the tax collector. (The natural instinct of survival can inspire a too strong desire for money) He befriended heavy drinkers.
King David had a weakness for women (sin of the flesh) he even had the husband, Uriah, of Bathsheba killed in the army's front lines to get his wife. He suffered by losing the child they had ...and yet God forgave him and went on to bless him. God understands our human weaknesses.
This question has been inspired by a question about lust that has been deleted, which I wanted to answer!