The Makkan suwar lay emphasis on oneness of ‘Allāh because

The Makkan Surahs (chapters) in the Quran lay emphasis on the oneness of 'Allāh because the pre-Islamic Makkans worshipped many gods. They believed in multiple deities and worshipped idols, which they kept in the Kaaba, the sacred mosque in Mecca. Therefore, the Makkan Surahs emphasized the oneness of 'Allāh, which is known as tawhid, to remind the Makkans that there is only one true God who created the heavens and the earth and that all worship and devotion should be directed to Him alone. Tawhid is the basis of the Islamic faith and is considered to be the most important article of faith in Islam. The Makkan Surahs also contained other articles of faith, such as the belief in the Day of Judgment, the Prophets, and the importance of doing good deeds, but the emphasis on the oneness of 'Allāh was the most important message conveyed in these chapters.