Sahih Muslim
The Book Pertaining to Repentance and Exhortation to Repentance (Kitab Al-Tauba)
Book Number: 037 / Hadith Number: 6628
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: When Allah created the creation, He ordained for Himself and this document is with Him: Verily, My mercy predominates Mv wrath.