جامع الترمذي

Ali [may Allah be pleased with him] narrated: that a Mukatib came to him and said: “Indeed I am not capable of my Kitabah so aid me.” He said: “Should I not teach you words that the Messenger of Allah (ﷺ) taught me? If you had a debt upon you similar to the mountain of Sir, Allah would fulfill it for you. He said: ‘Say: O Allah, suffice me with Your lawful against Your prohibited, and make me independent of all those besides You (Allāhummakfinī biḥalālika `an ḥarāmika, wa aghninī bi faḍlika `amman siwāka).’”