The Prophet of Allah ﷺ used to say at the end of his prayer, "O Allah, our Lord and Lord of all things, I bear witness that You alone are the Lord, having no partner."Ibrahim said it twice, "Our Lord and Lord of all things, I bear witness that Muhammad is Your servant and Your messenger. Our Lord and Lord of all things, I bear witness that all servants are brothers. O Allah, our Lord and Lord of all things, make me sincere to You, and my family as well, at every moment in this world and the next, Possessor of Majesty and Honor. Hear and answer. Allah is the Greatest, the Greatest. Allah is the Light of the heavens and the earth. Allah is the Greatest, the Greatest. Allah is sufficient for me, and the best Disposer of affairs. Allah is the Greatest, the Greatest."
حدثنا إبراهيم بن مهدي حدثنا معتمر قال سمعت داود الطفاوي يحدث عن أبي مسلم البجلي
كان نبي الله ﷺ يقول في دبر صلاته اللهم ربنا ورب كل شيء أنا شهيد أنك أنت الرب وحدك لا شريك لك قال إبراهيم مرتين ربنا ورب كل شيء أنا شهيد أن محمدا عبدك ورسولك ربنا ورب كل شيء أنا شهيد أن العباد كلهم إخوة اللهم ربنا ورب كل شيء اجعلني مخلصا لك وأهلي في كل ساعة من الدنيا والآخرة ذا الجلال والإكرام اسمع واستجب الله الأكبر الأكبر الله نور السماوات والأرض الله الأكبر الأكبر حسبي الله ونعم الوكيل الله الأكبر الأكبر
Its isnad is daif because of Dawud Tufawi, who is Dawud bin Rashid. Ibn Main and others declared him daif, while Ibn Hibban rated him reliable. Abu Muslim Bajali comes before him in the chain, and Ibn Hibban also rated him reliable. The hadith was narrated by Abu Dawud, 2/83, no. 1508, and by Tabarani in Al-Kabir, 5/210, no. 5122.