وَذَا ٱلنُّونِ إِذ ذَّهَبَ مُغَٰضِبًا فَظَنَّ أَن لَّن نَّقْدِرَ عَلَيْهِ فَنَادَىٰ فِى ٱلظُّلُمَٰتِ أَن لَّآ إِلَٰهَ إِلَّآ أَنتَ سُبْحَٰنَكَ إِنِّى كُنتُ مِنَ ٱلظَّٰلِمِينَ

Jonah (Yunus) was sent as a prophet to Nineveh, an ancient city of Iraq. At that time, Nineveh’s population was just over one hundred thousand. For a long time, he invited the community to accept the unity of God and the Hereafter, but they were not ready to do so. Now, if any community remains adamant about their denial of a prophet, even after having had the divine message conveyed to them to the fullest possible extent, then God’s way is to ask the prophet to leave the town and thereafter the community is subjected to punishment (in the shape of some disaster). But Jonah himself felt that the time had come for him to go, and he went away, leaving his community without waiting for God’s command to do so. He left the city and, reaching the sea coast, he boarded a boat. After setting sail, the boat started sinking. People thought that some slave who had fled from his master was on the boat. According to an old tradition, the solution to this problem was to discover the slave and cast him out. When lots were drawn, the name of Jonah came up and he was thrown overboard. At that moment a big fish (probably a sperm whale) appeared and swallowed him. The fish kept him in its stomach, then at God’s command, ejected him and cast him up on the coast. There he recovered his health and returned to his community. A prophet had to face this fate simply because he left his dawah mission before its completion. Then one can imagine the fate of those successors of the prophet who have been neglectful and completely unmindful of the task of spreading God’s word.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (21:87)