Jami` at-Tirmidhi Book 48, Hadith 217
“The Messenger of Allah (ﷺ) taught me, saying: ‘Say: “O Allah, make my secret better than my apparent condition, and make my apparent condition righteous. O Allah, I ask You for the righteous of what you give to the people, of wealth, wives, and children, not (to be) misguided, nor misguiding. (Allāhummaj`al sarīratī khairan min `alāniyatī waj`al `alāniyatī ṣāliha. Allāhumma innī as’aluka min ṣālihi mā tu’tin-nāsa minal-māli wal-ahli wal waladi, ghairaḍ-ḍāli wa lal-muḍil).”
“The best of supplication is the supplication of the Day of `Arafah. And the best of what I and the Prophets before me have said is: None has the right to be worshipped but Allah, Alone, without partner, to Him belongs all that exists, and to Him belongs the Praise, and He is powerful over all things. (Lā ilāha illallāh, waḥdahu lā sharīka lahu, lahul-mulku wa lahul-ḥamdu, wa huwa `alā kulli shai’in qadīr).’”
“I entered upon the Prophet (ﷺ) while he was praying and he had placed his left hand on his left thigh, and he had placed his right hand on his right thigh, and clasped his fingers, and extended his index finger, and he was saying: ‘O changer of the hearts, make my heart firm upon Your religion (Yā muqallibal-qulūbi thabbit qalbī `alā dīnik).’”