It is narrated from Ali bin Rabi'ah that he was riding behind Sayyiduna Ali (may Allah be pleased with him). When Sayyiduna Ali (may Allah be pleased with him) placed his foot in the stirrup, he said: 'Bismillah' (In the name of Allah). When he had settled upright on the animal's back, he said 'Alhamdulillah' (All praise is for Allah) three times and 'Allahu Akbar' (Allah is the Greatest) three times, then recited this verse: "Glorified is He who has subjected this to us, and we could not have controlled it (by ourselves)" [Surah al-Zukhruf: 13] . Then he said: 'La ilaha illa anta subhanaka, qad zalamtu nafsi, faghfir li dhunubi, innahu la yaghfiru al-dhunuba illa anta' (There is no god but You, glory be to You; I have wronged myself, so forgive me my sins, for none forgives sins except You). Then he leaned to one side and smiled. I asked: "O Commander of the Faithful! What made you laugh?" He replied: "I was riding behind the Prophet (peace and blessings be upon him), and the Messenger of Allah (peace and blessings be upon him) did exactly as I did. Then I asked him just as you asked me, and the Messenger of Allah (peace and blessings be upon him) said: 'Allah Almighty is greatly pleased with His servant when he says: La ilaha illa anta, inni qad zalamtu nafsi, faghfir li dhunubi, innahu la yaghfiru al-dhunuba illa anta, that is: O Allah, there is no true god but You; I have wronged myself, so forgive me my sins, for there is none who forgives except You. Then Allah says: My servant has recognized that he has a Lord who both forgives and punishes.'" This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.