Heb 12:10 For they verily for a few days chastened us after their own pleasure; but he for our profit, that we might be partakers of his holiness.
Chastening is God's sin-purging medicine, sent...to wither our fleshly aspirations, to detach our hearts from carnal objects, to deliver us from our idols, and to wean us more thoroughly from the world.
God has bidden us, put to death whatever in you is worldly: sexual immorality, impurity, lust, evil desire, and greed.
Col 3:5 Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry:
If we refuse to comply with this unpleasant task, then we may expect God Himself to use the pruning knife upon us!
My son, do not take the Lord's chastening lightly, or faint when you are reproved by Him.
Heb 12:5 And ye have forgotten the exhortation which speaketh unto you as unto children, My son, despise not thou the chastening of the Lord, nor faint when thou art rebuked of him:
This is a beneficial warning.
So far from despising the Lord's chastening, we should be grateful for it...
That God cares so much and takes such trouble with us, and that His bitter medicine produces such healthful effects.
No discipline seems pleasant at the time, but painful.
Later on, however, it produces a harvest of righteousness and peace for those who have been trained by it
Heb 12:11 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.
~Arthur Pink~