The Messenger of Allah ﷺ said, "When Allah decreed the creation, He wrote a decree that is with Him above the Throne, 'My mercy has overcome My wrath.'"
وقال رسول الله ﷺ لما قضى الله الخلق كتب كتابا فهو عنده فوق العرش إن رحمتي غلبت غضبي
This is also a sahih hadith, found in the individual manuscript (al-Sahifah al-Mufradah) under number 13, though the two sheikhs did not narrate it through this route, but rather through other routes.Bukhari narrated it at 208-209, 13:349, 370 (Fath), through the route of the Araj manuscript. Muslim likewise narrated it at 2:324 (Bulaq edition), through the route of the Araj manuscript, both in full and abridged form.Bukhari also narrated it at 13:325 (Fath), through the narration of Abu Salih from Abu Hurairah, and narrated it again at 13:349 (Fath) through the narration of Abu Rafi from Abu Hurairah.Muslim narrated it at 2:324 (Bulaq edition) through the narration of Ata bin Yasar from Abu Hurairah.This has already appeared in abridged form at 7297, through the route of the Araj manuscript, and has also appeared in full at 7491 and 7520, through the route of the Araj manuscript.