Because sentence against an evil work is not executed speedily, therefore the heart of the sons of men is fully set in them to do evil.
All Commentaries on Ecclesiastes 8:11 Go To Ecclesiastes 8
John Cassian
AD 435
Up until now, when you never gainsaid him either by your own or by anybody else’s response, you gave him leave to have the mastery in you, as Solomon says: “Because those who do evil are not quickly opposed, therefore the heart of the children of men is full within them, so that they may do evil.” And therefore, after he has been disclosed, this most wicked spirit will no longer be able to disturb you, nor shall the filthy serpent ever again seize a place to make his lair in you, now that by a salutary confession he has been drawn out from the darkness of your heart into the light. .