Musnad Ahmad 32:2033

Sulayman ibn Harb narrated to us, Hammad ibn Zayd narrated to us, from Thabit, from Anas ibn Malik, that a Jewish boy used to serve the Prophet, may Allah bless him and grant him peace. He became ill, so the Prophet, may Allah bless him and grant him peace, came to visit him. He sat by his head and said to him, "Accept Islam." He looked at his father, who was by his head, and he (the father) said, "Obey Abu al-Qasim." So he accepted Islam. The Prophet, may Allah bless him and grant him peace, went out from his presence saying, "Praise be to Allah who saved him from the Fire through me."