So the people of Nineveh believed God, and proclaimed a fast, and put on sackcloth, from the greatest of them even to the least of them.
All Commentaries on Jonah 3:5 Go To Jonah 3
Jerome
AD 420
LXX: similar. Nineveh believed but Israel did not believe; the foreskin believed, but circumcision remained without faith. First of all the men of Nineveh believed who had arrived at the age of Christ[150]: they announced a fast and dressed in sackcloth, from the greatest to the smallest of them. This regime and clothing is very worthy of penitence, so that those who had offended God through their indulgence or lust appeased him by condemning all that they had previously offended with. Sackcloth and fasting are the weapons of penitence, the rescue of sinners. First of all fasting, then sackcloth; first of all what is not seen, then what is visible; the one is always shown to God, the other sometimes to man. And if it were necessary to remove one from the two then I would rather keep fasting without sackcloth than have sackcloth without fasting. Elder men give the example which pertains to youths: for no one is without sin; and if his life only lasted one day, the years of his life would still be counted[151]. For if the stars are not pure before God, they are still more so than a worm or putrefaction, and those who are held by the sin of Adam, the great offender. Note here too the order, which is well written: God commands the prophet, the prophet proclaims to the city. First of all the men believe, announce fasting, and then everyone puts on sackcloth. The men do not announce the putting on of sackcloth, but only the fasting. All the same, with reason, those to whom penitence has been proscribed wear sackcloth and fast so that empty stomach and mourning clothes give the Lord more of an opportunity to remit.