It is narrated from Sayyiduna Zayd bin Arqam (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) used to recite this supplication after the prayer: "O Allah, You are our Lord and the Lord of everything; I bear witness that Muhammad (peace and blessings be upon him) is Your servant and Messenger. O Allah, You are our Lord and the Lord of everything; I bear witness that all the servants are brothers to one another. O Allah, You are our Lord and the Lord of everything; make me and my family sincere to You in this world and the Hereafter. O Possessor of Majesty and Honour, hear and answer. Allah is the Greatest, the Greatest. O Allah, You are the Light of the heavens and the earth. Allah is the Greatest, the Greatest. Allah is sufficient for me, and He is the best Disposer of affairs. Allah is the Greatest, the Greatest."
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 5103
Sayyiduna Zayd bin Arqam (may Allah be pleased with him) narrates that some people from among the Arabs came and said: "Take us to this man. If he is a prophet, we will be the most fortunate of people because of him, and if he is a king, we will live in his shelter." I went to the Messenger of Allah (peace and blessings be upon him) and told him (peace and blessings be upon him) what they had said. Then they came to the apartments of the Prophet (peace and blessings be upon him) and began calling out: "O Muhammad! O Muhammad!" The narrator said: So Allah, the Mighty and Majestic, revealed this verse: "Indeed, those who call you from behind the apartments, most of them do not understand" [Al-Hujurat: 4]. And the Messenger of Allah (peace and blessings be upon him) took hold of my ear and said: "O Zayd, Allah has confirmed the truth of your words."
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 5104