Muawiya wrote to Mughira bin Shuba asking what the Messenger of Allah ﷺ used to say after concluding the prayer. Mughira dictated the answer and wrote back to Muawiya, saying that the Messenger of Allah ﷺ used to say, "There is no god but Allah alone, with no partner. To Him belongs the dominion, to Him belongs all praise, and He has power over 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."
حدثنا مسدد قال حدثنا أبو معاوية عن الأعمش عن المسيب بن رافع عن وراد مولى المغيرة بن شعبة
كتب معاوية إلى المغيرة بن شعبة أي شيء كان رسول الله ﷺ يقول إذا سلم من الصلاة فأملاها المغيرة عليه وكتب إلى معاوية قال كان رسول الله ﷺ يقول 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
Muslim narrated it in "the book of Mosques, chapter on the recommendation of remembrance after prayer and a description of it," hadith no. 593, from the hadith of Abu Muawiya Dareer, and Bukhari narrated it in "the book of adhan, chapter on remembrance after prayer," hadith no. 844, from the hadith of Warrad, with this wording.