Sayyiduna Abu Hurairah, may Allah be pleased with him, narrates this statement of the Prophet Muhammad, peace and blessings be upon him: "When a servant commits a mistake, a dot is placed on his heart. Then if he separates himself, seeks forgiveness, and repents, it becomes clean. But if he commits the mistake again, it increases. Then if he commits the mistake again, it increases, until it overcomes him. This is the rust or (veil or covering) that Allah mentioned in these words: 'Beware! Rust has covered their hearts because of what they used to do.'"