Sayyiduna Abu Hurayrah (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) said: "Allah Almighty continues to accept the repentance of the servant as long as the death rattle has not come upon him."
Al-Bazzar recorded it; its chain contains Yazid bin Abd al-Malik al-Nawfali, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب التوبة / 17513