Sūrah Yāʾ-Sīn (Arabic: سورة يس‎‎) is the 36th surah of the Quran. It has 83 ayahs and is one of the Meccan surahs, although some scholars maintain that verse 12 is from the Medinan period. The name of the chapter comes from the two letters of the first verse of the chapter,[2] which has caused much scholarly debate, and which Tafsir al-Jalalayn, a Sunni tafsir, interprets by saying, "God knows best what He means by these." Yā Sīn is also one of the names of the Prophet Muhammad, as reported in a saying of Ali, "I heard the Messenger of God say, 'Verily God has named me by seven names in the Quran: Muhammad [3:144; 33:40; 47:2; 48:29], Ahmad [61:6], Tā Hā [20:1], Yā Sīn [36:1], thou enwrapped [al-Muzammil; 73:1], thou who art covered [al-Mudaththir; 74:1], and servant of God [ʿAbd Allāh; 72:19].'"

The surah focuses on establishing the Qur'an as a divine source, and it warns of the fate of those that mock God's revelations and are stubborn. The surah tells of the punishments that plagued past generations of nonbelievers as a warning to present and future generations. Additionally, the surah reiterates God's sovereignty as exemplified by His creations through signs from nature.

The surah ends with arguments in favor of the existence of Resurrection and God's sovereign power.

Heart of the Quran

It has been proposed that Yāʾ-Sīn is the "heart of the Quran". The meaning of “the heart” has been the basis of much scholarly discussion. The eloquence of this surah is traditionally regarded as representative of the miraculous nature of the Qur'an.It presents the essential themes of the Qur'an, such as the sovereignty of God, the unlimited power of God as exemplified by His creations, Paradise, the ultimate punishment of nonbelievers, resurrection, the struggle of believers against polytheists and nonbelievers, and the reassurance that the believers are on the right path, among others. Yā Sīn presents the message of the Qur'an in an efficient and powerful manner, with its quick and rhythmic verses. This surah asserts that Muhammad was not a poet, rather he was a great messenger of Allah.