Musnad Ahmad 1233:0

From the hadith of Tariq ibn Ashyam: He said: When a man would embrace Islam, the Prophet (ﷺ) would teach him prayer, then he would command him to supplicate with these words: "O Allah, forgive me, have mercy on me, guide me, grant me health, and provide for me." For these words gather for you your worldly life and your Hereafter.