Now I rejoice, not that you were made sorry, but that your sorrow led to repentance. For you were made sorry in a godly manner, that you might suffer loss from us in nothing. For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death. (2 Corinthians 7:9-10)
“The only form of dejection we should cultivate is the sorrow which goes with repentance for sin and is accompanied by hope in God. It was of this form of dejection that the Apostle said: ‘Godly sorrow produces a saving repentance which is not to be repented of’ (2 Cor 7:10). This ‘godly sorrow’ nourishes the soul through the hope engendered by repentance, and it is mingled with joy. That is why it makes us obedient and eager for every good work: accessible, humble, gentle, forbearing and patient in enduring all the suffering or tribulation God may send us. Possession of these qualities show that a man enjoys the fruits of the Holy Spirit: love, joy, peace, long-suffering, goodness, faith, self-control (cf. Gal. 5:22).
But from the other kind of dejection we come to know the fruits of the evil spirit: listlessness, impatience, anger, hatred, contentiousness, despair, sluggishness in praying. So we should shun this second form of dejection as we should unchastity, avarice, anger and the rest of the passions. It can be healed by prayer, hope in God, meditation on Holy Scripture, and by living with godly people.” (THE PHILOKALIA Vol 1, p 88)