Often it is said that if the repentance of Nineveh was genuine, why is there no record of it in Assyrian history and why did the effects of it not last into the future? For example, one hundred and sixty years later, during the time of Nahum, the Assyrians are marked for their cruelty towards other nations.
The fact that an earlier repentance is not mentioned by later historians should not surprise us; how many history books describe the religious revivals that Britain has known? Similarly, these periods of revival in Britain were followed by periods of decline, indicating that in some cases there were no long-lasting effects. In fact, it is often the case that the societies which are most hardened against God are the descendants of people who experienced revival. So these two objections are invalid. There is no reason not to believe that a genuine spiritual revival took place in Nineveh.
In fact, as we look at our society today this account of a revival in Nineveh should give us great encouragement. Our God can work today and do something similar on a vaster scale.
I would mention four details concerning their repentance. First, it was popular in the sense that it involved the entire city, including the government. Second, it was public in that all the inhabitants donned sackcloth and sat in ashes. The evidence of true penitence will always be seen by others, and is often an encouragement to others to repent. Third, the repentance was also deeply personal because each person was fully involved in confessing his or her sins. Fourth, their repentance was prompt because they did not wait until the thirty-ninth day to repent; instead they repented immediately.
What elements made up their repentance? They took seriously the word of God, they acknowledged the sovereignty of God, they stressed the necessity of earnest supplication to God, they stressed the need to cease from current known sins, and they hoped for the salvation of God. In other words, their repentance was genuine because it was marked by fear of God, apprehension of his judgement, separation from sin, and grief for their own sins.