Sayyiduna Usamah bin Sharik (may Allah be pleased with him) said: We were sitting with the Prophet (peace and blessings be upon him) as if birds were perched on our heads, with none of us speaking, when some people came and said: O Messenger of Allah, give us a verdict on such-and-such, give us a verdict on such-and-such. He (peace and blessings be upon him) said: "O people, Allah has removed harm, except for the one who assails (the honour of) his brother; he is the one who has fallen into harm and is ruined." (It was said:) O Messenger of Allah, should we seek medical treatment? He (peace and blessings be upon him) said: "Yes, Allah, the Mighty and Majestic, has not sent down any disease without also sending down a remedy for it, except for one disease." They said: O Messenger of Allah, what is it? He (peace and blessings be upon him) said: "Old age." They said: Then who among the servants of Allah is most beloved to Allah? He (peace and blessings be upon him) said: "The one among them who is best in character."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 468