The book of Jonah was probably written by Jonah though scholars seem to be divided on this. This book is read at the afternoon service of Yom Kippur, the holiest day of the Jewish year. On this day Jews fast and say prayers of penitence.
Yes, this is the book with the story about Jonah and the whale. God sent Jonah to preach to Nineveh, a great but wicked city. Nineveh stood on the eastern bank of the Tigris River. It had walls that were a hundred feet high and fifty feet thick. STOP. WHAT? 50 FEET THICK! WOW! The main wall had fifteen gates. That sounds like a lot, but that wall was over seven and a half miles long. The population of Nineveh was about 600,000 people including those who lived in the “suburb” outside the city walls. That population estimate is based on a curious verse we’ll look at last.
These residents were wicked idolaters who worshiped Asur and Ishtar, chief male and female deities. Most of the Assyrians worshiped them and since Assyria was a threat to Israel’s security (see Hosea 11:5 and Amos 5:27) this was one reason Jonah didn’t want to go to Nineveh. He was afraid that if the people did repent then God would not punish them and this did not sit well with his self-righteousness.