Now no chastening for the present seemeth to be joyous, but grievous: nevertheless afterward it yieldeth the peaceable fruit of righteousness unto them which are exercised thereby.
Joyous, but grievous - Greek, 'matter of joy ... of grief.' The objection that chastening is grievous is anticipated. It only 'seems' so to those being chastened, whose judgments are confused by present pain. Its ultimate fruit amply compensates for temporary pain. The real object of chastening is not that fathers find pleasure in children's pain. Gratified wishes would often be real curses (Psalms 106:15).
Afterward - the time often when God works.
Fruit of righteousness. Righteousness (springing from faith) is the fruit which chastening, the tree, yields (Philippians 1:11). "Peaceable" (cf. Isaiah 32:17; Isaiah 33:20-21; Isaiah 57:2); in contrast to the conflict by which it is won. As the olive garland, emblem of peace as well as victory, was put on the victor's brow in the games.
Exercised thereby - as athletes trained for a contest. Chastisement is the exercise to give experience, and make the spiritual combatant victorious (Romans 5:3). 'Happy the servant for whose improvement his Lord is earnest, with whom He deigns to be angry, whom He does not deceive by dissembling admonition' (Tertullian, 'De Pat.' 100: 11).