You may not believe in the literal creation BUT you better believe that Jonah was in the whale for 3 days…because Jesus said "just as Jonah was in the belly of the fish for 3 days, the Son of man will be in the earth for 3 days.
Jesus rose from the dead in 3 days…Unless you don’t believe that, either!
We also need to keep in mind that Jesus was using Jonah as an
example and an
allusion. The saying is not a statement to the effect that ‘Oh, Jonah was an actual, historical/factual person’, or even ‘Jonah was just a literary creation’, despite the way some folks read this passage. IMHO the example (the Son of Man will be on the heart of the earth
just like Jonah was in the belly of the sea monster for three days and three nights) does not stand or fall on Jonah being a (f)actual person or not.
Jesus or the early Christians are speaking a different language (both literally and figuratively speaking) than us, we need to remember that. They aren’t interested in questions many of us are currently preoccupied with such as whether the documentary hypothesis is true or not or whether the creation accounts in Genesis are word-for-word literal or whether David’s kingdom really existed or something along those lines. Jesus alluding to Jonah is not a statement about the work’s historicity. To read the saying in that way I think misses the whole point of the saying.
This quote addresses fundamentalists specifically, but I think it also holds water here:
The high status that the Old Testament holds in the minds of Jesus and the early Christians will be granted by the most critical as a matter of historical fact, and therefore the fundamentalist efforts to prove this are of no importance. On the other hand, the fundamentalist attempts to argue that these sayings of Jesus and the New Testament writers about Jonah, Daniel, Moses and other persons and events prove the historical accuracy of the Old Testament are futile, because they make no attempt to show that Jesus or the early Christians were interested in such questions as the authorship of books, the presence of sources, or the historical accuracy of data and figures.
I’m not saying that the Bible is in error or something, of course. What I am saying is, that in trying to prove the historicity of Scripture, cherry-picking every OT quotation or allusion made by Jesus or St. Paul and saying, “Oh look, Jesus alluded to Jonah! Since Jesus is God, that must mean Jonah’s story is factual!” is, from an outsider’s viewpoint (I’m thinking outside the box here) a rather weak/circular argument.