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'A'isha (Allah be pleased with her) reported: When we came to Medina, and it was an unhealthy, uncogenial place, Abu Bakr fell sick and Bilal also fell sick; and when Allah's Messenger (may peace be upon him) saw the illness of his Companions he said: O Allah, make Medina as congenial to us as you made Mecca congenial or more than that; make it conducive to health, and bleesus in its sa' and in its mudd, and transfer its fever to al-juhfa.