Musnad Ahmad 594:0

Wabisah ibn Ma'bad al-Asadi said: I came to the Messenger of Allah (ﷺ) and I wanted to leave nothing of righteousness and sin except that I asked him about it. He had a group of people around him, and I began to push through them until I said: "O Messenger of Allah, draw me near to you." So they let me approach until I sat between his hands. He said: "O Wabisah, shall I tell you what you came to ask me about, or will you ask me?" I said: "Nay, tell me." He said: "You came to ask me about righteousness and sin." I said: "Yes." So he gathered his fingers and struck my chest with them, saying: "O Wabisah, consult your heart, consult your soul." He said it three times. "Righteousness is that which the soul is tranquil with and the heart is tranquil with, and sin is that which wavers in the soul and fluctuates in the chest, even if people have given you a verdict and have given you a verdict."