Mughira bin Shuba dictated to me in a letter to Muawiya that the Prophet ﷺ used to say after every obligatory prayer, "There is no god but Allah alone, with no partner. To Him belongs the dominion, and to Him belongs all praise, and He is capable of all things. O Allah, none can withhold what You grant, and none can grant what You withhold, and no fortune can benefit its possessor against You."
أملى علي المغيرة بن شعبة في كتاب إلى معاوية: أن النبي ﷺ كان يقول في دبر كل صلاة مكتوبة: لا إله إلا الله وحده لا شريك له، له الملك، وله الحمد، وهو على كل شيء قدير. اللهم لا مانع لما أعطيت، ولا معطي لما منعت، ولا ينفع ذا الجد منك الجد.
Bukhari narrated it in the Book of Adhan (844), and Muslim in the Book of Mosques (593), both through the route of Warrad, the scribe of Mughira bin Shuba, who said, and he mentioned it.