Jesus quoted Jonah as having been, “In the belly of the whale for three days and three nights.”
Do we need to believe that Jonah spent three days in the belly of a whale? I don’t think so. The story of Jonah was written around the year 400. We can tell that from its use of words that were current then. (When a movie pops up on television we can see that it dates from the nineteen thirties or fifties or from two thousand and ten. So, from the distinctive wording of the Book of Jonah, we can see that it was written around the year 400.)
In 450 B.C. Jerusalem was visited by two prominent Jews whose family had stayed behind in Persia at the end of the seventies years of the Babylonian captivity. Those two had been sent to a Jerusalem whose morals had become so lax that the city was falling apart. To straighten the city, they imposed some strict rules, including ones about avoiding contact with non Jews.