So the people of Nineveh believed God, and proclaimed a fast, and put on sackcloth…
How came the Ninevites to believe God, as no hope of salvation was given them? For there can be no faith without an acquaintance with the paternal kindness of God; whoever regards God as angry with, him must necessarily despair. Since, then, Jonah gave them no knowledge of God's mercy he must have greatly terrified the Ninevites, and not have called them to faith. The answer is, that the expression is to be taken as including a part for the whole; for there is no perfect faith when men, being called to repentance, do suppliantly humble themselves before God; but yet it is a part of faith, for the apostle says in Hebrews 11., that Noah through faith feared; he deduces the fear which Noah entertained on account of the oracular word he received from faith, showing thereby that it was faith in part, and pointing out the source from which it proceeded. At the same time, the mind of the holy patriarch must have been moved by other things besides threatenings when he built an ark for himself as the means of safety. We may thus, by taking a part for the whole, explain this place — that the Ninevites believed God; for as they knew that God required the deserved punishment, they submitted to Him, and at the same time solicited pardon; but the Ninevites derived from the words of Jonah something more than mere terror, for had they only apprehended this — that they were guilty before God, and were justly summoned to punishment, they would have been confounded and stunned with dread, and could never have been encouraged to seek forgiveness. Inasmuch, then, as they suppliantly prostrated themselves before God, they must certainly have conceived some hope of grace. They were not, therefore, so touched with penitence and the fear of God but that they had some knowledge of Divine grace; thus they believed God, for though they were aware that they were most worthy of death, they yet despaired not, but betook themselves to prayer. They must therefore have derived more advantage from the preaching of Jonah than the mere knowledge that they were guilty before God.
( John Calvin.)
Parallel VersesKJV: 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.