Sahih Muslim
The Book Pertaining to Repentance and Exhortation to Repentance (Kitab Al-Tauba)
Book Number: 037 / Hadith Number: 6630
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: Allah created one hundred (parts of mercy) and He distributed one amongst His creation and kept this one hundred excepting one with Himself (for the Day of Resurrection).