Hadith 653:4
Mus'ab ibn Salam narrated to us, Al-Ajal narrated to us, from Ziyad ibn 'Alaqah, from Usamah ibn Sharik, a man from his people, who said: A Bedouin came to the Messenger of Allah, may Allah bless him and grant him peace, and said: "O Messenger of Allah, which of the people is best?" He said: "The best of them in character." Then he said: "O Messenger of Allah, should we seek medical treatment?" He said: "Seek medical treatment, for Allah has not sent down a disease except that He has sent down for it a cure; those who know it know it, and those who are ignorant of it are ignorant of it."
حدثنا مصعب بن سلام، حدثنا الأجلح، عن زياد بن علاقة، عن أسامة بن شريك رجل من قومه، قال: جاء أعرابي إلى رسول الله صلى الله عليه وسلم، فقال: يا رسول الله، أي الناس خير؟ قال: " أحسنهم خلقا " ثم قال: يا رسول الله، أنتداوى؟ قال: " تداووا، فإن الله لم ينزل داء، إلا أنزل له شفاء، علمه من علمه، وجهله من جهله "