Jonah A.S was a prophet of God as mentioned in Bible adn Quran as well, that He was sent as a prophet towards people of Nineveh, because itheir wickedness has come up before God. but he got distressed early and left in the seas leaving his people behind. A big storm came up in his ship and he got swallowed by a big whale. Their in the belly of that whale he stayed for some days in shear darkness, repenting to God for his mistake of leaving his people behind doing wrongdoings in the society as Jonah was supposed to preach them or atleast spent his life trying for that good deed. Jonah repented “There is no deity except You; exalted are You. Indeed, I have been of the wrongdoers.”
Surah al-Anbiya (21:87)