Messenger of Allah ﷺ said, "When Allah completed the creation, He wrote in His Book which is with Him on His Throne, "My Mercy overpowers My Anger." (Using translation from Bukhārī 3194)   

أَنَّ النَّبِيَّ ﷺ قَالَ «لَمَّا قَضَى اللهُ الْخَلْقَ كَتَبَ فِي كِتَابِهِ فَهُوَ عِنْدَهُ فَوْقَ الْعَرْشِ إِنَّ رَحْمَتِي غَلَبَتْ غَضَبِي» اللَّفْظُ لِقُتَيْبَةَ  

[Machine] The Messenger of Allah ﷺ said, "When Allah finished creating, He wrote on His throne, 'My mercy precedes my wrath.'" Abu Dawud said, "My mercy overcomes my wrath and it is above the throne."  

قَالَ رَسُولُ اللهِ ﷺ «لَمَّا فَرَغَ اللهُ مِنَ الْخَلْقِ كَتَبَ عَلَى عَرْشِهِ إِنَّ رَحْمَتِي سَبَقَتْ غَضَبِي» قَالَ أَبُو دَاوُدَ «رَحْمَتِي تَغْلِبُ غَضَبِي وَهُوَ فَوْقَ الْعَرْشِ»