Theophylact of Ohrid, on Heb 12:11

“Now all chastisement for the present indeed seemeth not to bring with it joy, but sorrow: but afterwards it will yield, to them that are exercised by it, the most peaceable fruit of justice.”

“Again from a common thought he took occasion for persuasion and says: "all chastening," both divine and human, "seems not to be joy, but grief." He excellently says: "seems," for in reality it is not grief. For how could it properly be grief, being the mother of joy? But with reference to us, who are discontented with discipline, it is said: "seems." "But afterward it yields the peaceful fruit of righteousness to those who have been trained by it." What does "peaceful" mean? – that is, unshakeable, easy, pleasant. For the one who grieves feels turmoil, while the one who rejoices feels a certain lightness and tranquility. This is the fruit of righteousness, because God, being righteous, gives rest there to those who were grieved in this age. See then that he calls discipline exercise (γυμνασίαν), since it strengthens believers and makes them, as it were, athletes and more steadfast. So why do you avoid that which strengthens your souls?”

Imported from an open dataset — not yet checked against the printed edition.