Sayyiduna Safwan bin Assal (may Allah be pleased with him) narrates: The Messenger of Allah (peace and blessings be upon him) came out to us and began narrating to us: "Repentance has a door, the width between its two leaves being the distance between the east and the west. It will not be closed until the sun rises from the west." Then the Messenger of Allah (peace and blessings be upon him) recited this verse: "On the day some of the signs of your Lord come, no soul will benefit from its faith if it had not believed before or earned some good through its faith." [Surah al-An'am: 158]
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7352