And Jonah began to enter the city on the first day's walk. Then he cried out and said, "Yet forty days, and Nineveh shall be overthrown!"
Jonah 3:4
Surrounding context
3:3 So Jonah arose and went to Nineveh, according to the word of the LORD. Now Nineveh was an exceedingly great city, a three-day journey in extent.
3:4 And Jonah began to enter the city on the first day's walk. Then he cried out and said, "Yet forty days, and Nineveh shall be overthrown!"
3:5 So the people of Nineveh believed God, proclaimed a fast, and put on sackcloth, from the greatest to the least of them.