And Jonah began to enter into the city a day's {c} journey, and he cried, and said, Yet forty days, and Nineveh shall be overthrown.

(c) He went forward one day in the city and preached, and so he continued until the city was converted.

Wesley's Notes

3:4 Shall be overthrown - The threat is express. But there was a reserve with God, on condition of repentance.

Jamieson-Fausset-Brown Bible Commentary

4. a day's journey-not going straight forward without stopping: for the city was but eighteen miles in length; but stopping in his progress from time to time to announce his message to the crowds gathering about him.

Yet forty days, and Nineveh shall be overthrown-The commission, given indefinitely at his setting out, assumes now on his arrival a definite form, and that severer than before. It is no longer a cry against the sins of Nineveh, but an announcement of its ruin in forty days. This number is in Scripture associated often with humiliation. It was forty days that Moses, Elijah, and Christ fasted. Forty years elapsed from the beginning of Christ's ministry (the antitype of Jonah's) to the destruction of Jerusalem. The more definite form of the denunciation implies that Nineveh has now almost filled up the measure of her guilt. The change in the form which the Ninevites would hear from Jonah on anxious inquiry into his history, would alarm them the more, as implying the increasing nearness and certainty of their doom, and would at the same time reprove Jonah for his previous guilt in delaying to warn them. The very solitariness of the one message announced by the stranger thus suddenly appearing among them, would impress them with the more awe. Learning from him, that so far from lightly prophesying evil against them, he had shrunk from announcing a less severe denunciation, and therefore had been cast into the deep and only saved by miracle, they felt how imminent was their peril, threatened as they now were by a prophet whose fortunes were so closely bound up with theirs. In Noah's days one hundred twenty years of warning were given to men, yet they repented not till the flood came, and it was too late. But in the case of Nineveh, God granted a double mercy: first, that its people should repent immediately after threatening; second, that pardon should immediately follow their repentance.

Matthew Henry's Concise Commentary

3:1-4 God employs Jonah again in his service. His making use of us is an evidence of his being at peace with us. Jonah was not disobedient, as he had been. He neither endeavoured to avoid hearing the command, nor declined to obey it. See here the nature of repentance; it is the change of our mind and way, and a return to our work and duty. Also, the benefit of affliction; it brings those back to their place who had deserted it. See the power of Divine grace, for affliction of itself would rather drive men from God, than draw them to him. God's servants must go where he sends them, come when he calls them, and do what he bids them; we must do whatever the word of the Lord commands. Jonah faithfully and boldly delivered his errand. Whether Jonah said more, to show the anger of God against them, or whether he only repeated these words again and again, is not certain, but this was the purport of his message. Forty days is a long time for a righteous God to delay judgments, yet it is but a little time for an unrighteous people to repent and reform in. And should it not awaken us to get ready for death, to consider that we cannot be so sure that we shall live forty days, as Nineveh then was that it should stand forty days? We should be alarmed if we were sure not to live a month, yet we are careless though we are not sure to live a day.