Question: In Jonah 3:4, the prophet says that Nineveh will be destroyed in 40 days. But it wasn't destroyed. Doesn't Jonah 3:10 admit that it wasn't destroyed? In Jonah 3:10 the prophet says that Nineveh wasn't destroyed because the people of Nineveh had repented. Isn't Jonah 3:10 simply trying to clean up the fact that he had a failed prophecy in Jonah 3:4?
Response: Jonah's prophecy, as represented in Jonah 3:4, was completely and literally fulfilled after the 40 days.
But there are two reasons why people sometimes overlook this fact:
1. By making the assumption that the key Hebrew word, haphak, must be translated into English as "destroyed," rather than as "transformed," or "overturned," or "changed," etc.
2. And by making the assumption that the English word "destroyed" must always consist of a physical destruction.
There are some English translations of the Bible that translate haphak as "destroyed," which is an acceptable translation, so long as the reader doesn't jump to the conclusion that the destruction must be a physical one.
The CEV English translation of the Bible, for example, renders Jonah 3:4 like this:
After walking for a day, Jonah warned the people, "Forty days from now, Nineveh will be destroyed!" - Jonah 3:4 (CEV).
According to the KJV Concordance that is available through www.BlueLetterBible.org, the Hebrew word haphak is used about 90 times in the Old Testament. That concordance shows that the word is most often translated into English as "turn," or "turned," or "transformed," or "changed," or "turned away," or "turned from."
Most of the time, the word haphak refers to some sort of change or transformation. And, if you look at how the word is used in various Bible passages, you will see that most of the time, haphak refers to a transformation that doesn't involve a physical destruction.
And, as Jonah explains in verse 10, Nineveh did change, Nineveh was transformed, because the people had turned away from their sins and repented. And, as Jonah explains, if the people had not repented, their transformation then would have involved a physical destruction. Either way, the prophecy of Jonah 3:4 would have been completely and literally fulfilled, because haphak refers to a transformation that may or may not involve a physical destruction.
In other words, Nineveh would have been transformed after 40 days, just like the prophecy said, whether through repentance or through physical destruction.