عجباً للمؤمن لايقضي اللّه عليه قضاءً إلا كان خيراً له، سرّه او ساءه. إن ابتلاه كان كفّارةً لذنبه، وإن اعطاه وأكرمه كان قد حباه
The believer’s situation is a strange one: Allah does not determine anything for him unless he is certain to benefit from it whether it makes him sad or happy. If He causes him to be sad, it is the retribution for his sins, and if He bestows a blessing on him, He has given him something.
(Tohfatul Oqul, p. 48)
Whatever God has determined for the believer is for his own good: both such events as diseases that make him sad and the events that cheer him up. The saddening events are the atonement for sins, and delightful events are Allah's blessings. We have the same theme in Hafiz's poems, but he believed that it is only true of the mystic. This tradition, however, says that it refers to all believers.