Midrash su Giobbe 33:25

R. Alexandria said in the name of R. Chiya b. Abba: "A sick person does not recover from his sickness until all his sins are forgiven, as it is said (Ps. 103, 3) Who forgiveth all thy iniquities should heal all thy diseases." R. Hamnuna said: "Such a person regains his youthful days, as it is said (Job 33, 25) His flesh becometh full again as in youth; he returneth to the days of his boyhood." (Ps. 41, 4) Mayest Thou turn all his lying down in his sickness. R. Joseph said: "This means that he forgets his learning."