The Holy One--blessed be He!--often brings affliction on the righteous
though they have not sinned, in order that they may learn to keep aloof
from the allurements of the world and eschew temptation to sin. From
this it is plain that afflictions are good for man, and therefore our
Rabbis, of blessed memory, have said, "As men bless with joy and a
sincere heart for a benefit received, so likewise ought they joyfully to
bless God when He afflicts them, as, though the special blessing be
hidden from the children of men, such affliction is surely intended for
good.... Or most souls being at present in a state of transmigration,
God requites a man now for what his soul merited in a bypast time in
another body, by having broken some of the 613 precepts."
THE KABBALA, _Kitzur Sh'lu_, p. 6, col. 1.