Sayyiduna Usamah bin Sharik (may Allah be pleased with him) said: I was present with the Prophet (peace and blessings be upon him) when Bedouins came to him (peace and blessings be upon him) from his right and his left, asking: O Messenger of Allah, is there any harm upon us in such-and-such? (They repeated this question) twice. The Messenger of Allah (peace and blessings be upon him) said: "Allah, the Mighty and Majestic, has removed harm, except for the one who unjustly assails a Muslim" - or he said: "with injustice" - "he is the one who has fallen into harm and is ruined." They said: O Messenger of Allah, should we seek treatment for such-and-such an illness? (They repeated this question) twice. He (peace and blessings be upon him) said: "Yes, seek treatment, for Allah, the Mighty and Majestic, has not sent down any disease without also sending down its cure, except for one disease: (it is) old age." They said: O Messenger of Allah, what is the best thing people have been given? He (peace and blessings be upon him) said: "Good character."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 479