Musar על עירובין 36:11

Every man can learn from David in the matter of repentance. And so do we find with Adam. When Adam saw that the world was punished with death because of his deed he sat fasting one hundred and thirty years, and separated himself from his wife and covered his body with garlands of figs (to remind him constantly of his sin in eating the fruit of the forbidden tree) (Erubin 18b).