9 Be afflicted, and mourn, and weep: let your laughter be turned to mourning, and your joy to heaviness.
[AD 500] Desert Fathers on James 4:7-10
A hermit said, ‘If anyone says “Forgive me”, and humbles himself, he burns up the demons that tempt him.’

[AD 407] John Chrysostom on James 4:9
The person who repents after sinning is worthy of blessings, not of mourning, as he returns to the company of the righteous. First, confess your sins that you may be justified, for if someone is not ashamed of his sin he is miserable, not so much because he fell from grace but because he has remained in his fallen state. And if it is a wicked thing not to repent after sinning, what punishment will someone deserve who sins as a matter of course? If a person overcome with the need to repent is unclean, what forgiveness will there be for someone who suffers because he remains in his sins?

[AD 601] Leander of Seville on James 4:9
Flee laughter as a sin and change temporal joy into mourning so that you may be blessed, for those who mourn are blessed and shall be comforted.

[AD 735] Bede on James 4:9
Be miserable, mourn and weep. Let your laughter be turned to mourning and your joy to gloom. Humble yourselves in the presence of the Lord, and He will exalt you. Do not, He says, love to become wealthy and rejoice in this world, but being mindful of the sins you have committed, rather aim that through the brief miseries, poverty and transient lamentation of this life you may reach the eternal joys of the heavenly kingdom, so that you do not, for the temporary joy of wealth which you have acquired through unjust labor, perpetually beg, mourn, and pay the penalties in torment.