When I became sick the doctor said to me: "Verily your research and Islamic lecturing increases your illness."

I (Ibn Taymiyyah) replied: "I cannot stop, and I will debate you in your knowledge! If a person becomes happy and joyful doesn’t this strengthen their soul or spirit, and as a result wards off illness? "

The doctor responded: "Of course." 

So I (Ibn Taymiyyah) said: "Verily my spirit is pleased with knowledge and it strengthens my nature and due to that I find relaxation." 



[Reported by Ibn al Qayyim in his book: “Rawdatul Muhibeen”, he was informed by it by his Sheikh (Ibn Taymiyyah) ]