The period of its revelation is the same as of Surah Maryam. It is just possible that it was sent down during the Migration to Habash or just after it. Anyhow, it is certain that this Surah was revealed before Hadrat Umar embraced Islam.
According to a well known and authentic tradition when Hadrat Umar set out to kill the Holy Prophet, he met a certain person, who said, "Before you do anything else, you should know that your own sister and brother-in-law have embraced Islam" Hearing this, he directly went to the house of his sister. There he found his sister, Fatimah, and his brother-in-law, Said bin Zaid, learning the contents of a scroll from Khabbab bin Art. When Fatimah saw him coming she hid the scroll at once, but Hadrat Umar had heard the recital, so he began to interrogate them about it. Then he began to thrash his brother-in-law, and wounded his sister, who tried to protect him. At last both of them confessed, "We have become Muslims; you may do whatever you like." As Hadrat Umar was moved to see blood running down from her head, he said, "Show me the thing you were reading." The sister asked him to promise on oath that he would not tear it, and added, "You cannot touch it unless you have a bath." Accordingly, Hadrat Umar took his bath and when he began to read the scroll, which contained this Surah, he spontaneously spoke out, "What an excellent thing!" At this Hadrat Khabbab, who had hidden himself at the sound of his footsteps, came out of his hiding and said, "By God, I have high expectations that Allah will get great service from you to propagate the Message of His Prophet, for just yesterday I heard the Holy Prophet praying to Allah, 'My Lord, make Abul Hakam bin Hisham (Abu Jahl) or Umar bin Khattab a supporter of Islam. So O Umar, turn to Allah, turn to Allah." These words proved to be so persuasive that he at once accompanied Hadrat Khabbab and went to the Holy Prophet to embrace Islam. This happened a short time after the Migration to Habash.
This Surah begins with the enunciation of the object of the Revelation of the Qur'an to this effect:"O Muhammad, this Quran has not been sent down to you to put you unnecessarily to some great affliction. It does not demand from you to perform the impossible task of imbuing the hearts of the obdurate disbelievers with Faith. It is merely an admonition meant to guide on to the Right Path those who fear God and want to save themselves from His punishment. This Quran is the Word of the Master of the earth and the heavens and God-head belongs to Him alone:These two facts are eternal whether one believes them or not."
After this introduction, the Surah abruptly moves on to relate the story of Prophet Moses without any apparent relevancy and without even hinting at its applicability to the events of the period. However, if we read between the lines, we realize that the discourse is addressed very relevantly to the people of Makkah. But before we explain the hidden meaning of the discourse, we must keep in view the fact that the Arabs in general acknowledged Moses as a Prophet of God. This was so because they had "been influenced by the large number of the Jews around them and by" the neighboring Christian kingdoms. Now let us state those things which are hidden between the lines of the story:
Allah does not appoint a Prophet by the beat of drums or My celebrating the occasion in a regular and formal ceremony, as if to say, "We are appointing such and such a person as Our Prophet from today." On the contrary, He bestows Prophethood in a confidential manner just as He did in the case of Prophet Moses. Therefore you should not consider it strange if Hadrat Muhammad has been appointed as a Prophet all of a sudden and without any public proclamation.
Prophet Muhammad has been made the standard bearer of the Message of the Truth among the people of the Quraish all by himself without material provisions, just as Prophet Moses was entrusted with the Mission to go to a tyrant king like Pharaoh and ask him to give up his attitude of rebellion. These are the mysterious ways of Allah. He catches hold of a way farer of Midian on his way to Egypt and says, "Go and fight with the greatest tyrant of the time." He did not provide him with armies and provisions for this Mission. The only thing He did was to appoint his brother as his assistant at his request.
You, O People of Makkah, should note it well that Pharaoh employed the same devices against Prophet Moses as you are employing against Prophet Muhammad -- frivolous objections, accusations, and cruel persecutions. You should know that Allah's Prophet came out victorious over Pharaoh, who possessed large armies and war equipments. Incidentally, the Muslims have been consoled and comforted, though not in so many words, that they should not be afraid of fighting with the Quraish against fearful odds, for the mission which is supported by Allah comes out victorious in the end. At the same time, the Muslims have been exhorted to follow the excellent example of the magicians of Egypt, who remained steadfast in their Faith, though Pharaoh threatened them with horrible vengeance.
An incident from the story of the Israelites has been cited to show in what ridiculous manner the idolization of false gods and goddesses starts and that the Prophets of God do not tolerate even the slightest tinge of this preposterous practice. Likewise, Prophet Muhammad is following the former Prophets in opposing shirk and idol worship today.
Thus, the story of Moses has been used to throw light on all those matters which were connected with the conflict between the Holy Prophet and the Quraish. Then at the end of the story, the. Quraish have been briefly admonished, as if to say, "The Quran has been sent down in your tongue for your own good. If you listen to it and follow its admonition, you will be doing so for your own good but if you reject it, you will yourselves meet with an evil end."
After this the story of Prophet Adam has been related, as if to tell the Quraish, "The way you are following is the way of Satan, whereas the right way for a man is to follow his father Adam. He was beguiled by Satan, but when he realized his error, he plainly confessed it and repented and again turned back to the service of Allah and won His favor. On the other hand, if a person follows Satan and sticks to his error obdurately in spite of admonition, he does harm to himself alone like Satan."
In the end, the Holy Prophet and the Muslims have been advised not to be impatient in regard to the punishment to the disbelievers, as if to say, "Allah has His Own scheme concerning them. He does not seize them at once but gives them sufficient respite. Therefore you should not grow impatient but bear the persecutions with fortitude and go on conveying the Message."
In this connection, great emphasis has been laid on Salat so that it may create in the believers the virtues of patience, forbearance, contentment, resignation to the will of God and self analysis for these are greatly needed in the service of the Message of the Truth.