This Surah was revealed during the very early stage at Makkah.
An Admonition to believe in Allah, Who is the provider of your sustenance.
To understand this Surah it is necessary to know the historical background of the tribe of Qureysh. It was scattered throughout Hijaz until the time of Qusayy bin Kilab, the ancestor of the Prophet (pbuh). First of all, Qusayy gathered his tribe in Makkah and the tribe was able to gain authority over the Ka'bah. On that very basis, Qusayy was called Mujammi (uniter, assembler) by his people. This man, by his sagacity and wisdom, founded a city state in Makkah and made excellent arrangements for the welfare of the pilgrims coming from all over Arabia, with the result that the Qureysh were able to gain great influence among the Arabian tribes and lands. After Qusayy's death, the offices of the state of Makkah were divided between his sons, Abdi Manaf and Abd ad-Dar, but of the two Abdi Manaf gained greater fame even during his father's lifetime and was held in high esteem throughout Arabia.
Abdi Manaf had four sons; Hashim, Abdi Shams, Al-Muttalib, and Naufal. Of these, Hashim, father of Abdul Muttalib and grandfather of the Prophet, first conceived the idea to take part in the trade that passed between the eastern countries, Syria and Egypt through Arabia. He also purchased the necessities of life for the Arabians so that the tribes living by the trade route bought these from them and the merchants living in the interior of the country were attracted to the market of Makkah. This was the time when the Sasanian kingdom of Iran had gained control over the international trade that was carried out between the northern lands, the eastern countries and the Byzantine empire through the Persian Gulf. This boosted the trade activity on the trade route leading from southern Arabia to Syria and Egypt along the Red Sea coast. As with the other Arabian caravans, the Qureysh took advantage of the fact that the tribes on this route held them in high esteem because of their status of being Keepers of the Ka'bah. They stood indebted to them for the great generosity with which the Qureysh treated them in the Hajj season. That is why the Qureysh felt no fear that their caravans would be robbed or harmed any where along the way. The tribes along the way did not even charge them the heavy transit taxes that they demanded from the other caravans. Hashim, taking advantage of this, prepared the trade scheme and made his three brothers partners in it. Thus, Hashim obtained trade privileges from the Ghassanide king of Syria, Abdi Shams from the Negus, Al-Muttalib from the Yamanite nobles and Naufal from the governments of Iraq and lran, and their trade began to flourish. That is how the four brothers became famous as traders and began to be called Ashab Al-Ilaf (generators of love and affection) on account of their friendly relations with the tribes and states of the surrounding lands.
Because of their business relations with Syria, Egypt, Iraq, Iran, Yaman and Abyssinia, the Qureysh became the most affluent tribe in Arabia and Makkah became the most important commercial center of the Arabian peninsula. Another great advantage that accrued from these international relations was that the caravans brought from Iraq tile script which later was used for writing down the Qur'an. No other Arabian tribe could boast of so many literate people as Qureysh. For these very reasons, the Prophet (pbuh) said: "The Qureysh are the leaders of men." (Musnad Ahmed: Marwiyat Amr bin al-As).
The Qureysh were thus prospering and flourishing when the event of Abrahah's invasion of Makkah took place. Had Abrahah succeeded in taking this Holy City and destroying the Ka'bah, the glory and renown of not only the Qureysh, but of the Ka'bah itself, would have suffered a great setback. The belief of pre-Islamic Arabia that the House indeed was Allah's House, would have been shattered, and the high esteem in which the Qureysh were held for being keepers of the House throughout the country would have been tarnished. Then, after the Abyssinian advance to Makkah, the Byzantium also would have taken the initiative to gain control over the trade route between Syria and Makkah. The Qureysh would have been reduced to a plight worse than that in which they were involved before Qusayy bin Kilab. But when Allah showed this manifestation of His power where swarms of birds destroyed 60,000 Abyssinian troops brought by Abrahah by pelting them with stones, from Makkah to Yaman they continued falling and dying by the wayside. The faith of the Arabs that the Ka'bah indeed was Allah's House, increased manifold, and the glory and renown of Qureysh was also enhanced considerably throughout the country. Now the Arabs were convinced that they were under Allah's special favor. They, therefore, visited every part of Arabia fearlessly and passed through every land with their trade caravans unharmed. No one would dare touch them with an evil intention. Not to speak of touching them, even if they had a non-Qureyshite under their protection, he too was allowed to pass unharmed. That is why in this Surah, the Qureysh are simply asked to consider; "When you yourselves acknowledge this House (i.e. The Ka'bah) to be Allah's House, and not of the idols, and when you fully know that it is Allah Alone Who has granted you peace by virtue of this House, made your trade and commerce flourish and favored you with prosperity, you should then worship none but Him Alone!"