It is narrated from Sayyiduna Safwan bin Assal (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings be upon him) visited a Jewish boy who was ill, and he (peace and blessings be upon him) said: "Do you bear witness that there is no true god except Allah?" He said: Yes. He (peace and blessings be upon him) said: "Do you bear witness that Muhammad (peace and blessings be upon him) is His servant and Messenger?" He said: Yes. Then he died, and the Messenger of Allah (peace and blessings be upon him) and the Muslims took charge of preparing him for burial; they washed him and buried him.
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7359