The Sura takes its name from V. 98 in which there is a reference to Prophet Yunus (Jonah). The name as usual is symbolical and does not indicate that the Sura deals with the story of Prophet Jonah.
Period of Revelation
We learn from traditions and this is supported by the contents of the Sura itself that the whole of this Sura was revealed at Makkah. But there are some people who are of the opinion that some of its verses were revealed at Al-Madinah. This is however a superficial view. The continuity of the theme clearly shows that this does not comprise isolated verses or discourses that were revealed at different times and on different occasions. On the contrary it is from the beginning to the end a closely connected discourse which must have been revealed at one sitting. Besides this the nature of its theme is itself a clear proof that the Sura belongs to the Makkan period.
Time of Revelation
We have no tradition in regard to the time of it's revelation but its subject matter gives clear indication that it must have been revealed during the last stage of the Holy Prophet's residence at Makkah. For the mode of the discourse suggests that at the time of its revelation the antagonism of the opponents of the Message had become so intense that they could not tolerate even the presence of the Holy Prophet and his followers among themselves and that things had come to such a pass as to leave no hope that they would ever understand and accept the Message of the Prophet. This indicates that the last stage of the Prophet's life among thee people had come and the final warning like the one in this Sura had to be given. These characteristics of the discourse are clear proof that it was revealed during the last stage of the Movement at Makkah. Another thing that determines more specifically the order of the Suras of the last stage at Makkah is the mention (or absence) of some open or covert hint about Hijrat (Emigration) from Makkah. As this Sura does not contain any hint whatsoever about this it is a proof that it preceded those suras which contain it. Now that we have specified the time of its revelation there is no need of repeating its historical background because that has already been stated in Suras VI and VII.
This discourse deals with the invitation to the Message admonition and warning. In the very introductory verses the invitation has been extended like this:- "The people consider it a strange thing that this Message is being conveyed by a human being and charge him with sorcery whereas there is nothing strange in it nor has it any connection with sorcery or sooth saying. It simply informs you of two realities. First Allah Who has created the universe and manages it is in fact your Master and Lord and He alone is entitled to your worship. The second reality is that after the life in this world there will be another life in the Next World where you shall have to render full account of the life of this world and be rewarded or punished according to whether you adopted the righteous attitude as required by Him after acknowleding Him as your Masters or acted against His will. Both of these realities which the Messenger is presenting before you are "realities" in themselves whether you acknowledge them as such or not. He is inviting you to accept these and regulate your lives in accordance with them; if you accept these you will have a very blessed end; otherwise join shall meet with evil consequences."