Yā Sīn [1] (also Yaseen; Arabic: يس‎) is the 36th sūrah of the Quran. It has 83 verses (āyāt). Regarding the timing and contextual background of the supposed revelation (asbāb al-nuzūl), it is an earlier "Meccan surah", which means it is believed to have been revealed in Mecca, instead of later in Medina. Some scholars maintain that verse 12 is from the Medinan period.[2]

The surah is named "yā sīn" because it starts with the "disconnected" or "mysterious" (muqatta'at) Arabic letters: يس (yā sīn).[3] The meaning of these letters was debated between Islamic scholars and a consensus was reached. One of the interpretations is "O human being!" referring to Muhammad since the verses that follow are translated as "By the Qur´an, full of Wisdom, Thou art indeed one of the messengers".[4] Tafsir al-Jalalayn, a Sunni beginners exegesis (tafsir), concludes, "God knows best what He means by these [letters]."[5]

Yasin is also one of the names of Muhammad,[6][7][8] 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), Ṭā-Hā, (20:1), Yā Sīn (36:1), thou enwrapped (Al-Muzzammil; 73:1), thou who art covered (Al-Muddathir; 74:1), and servant of God (ʿAbd Allāh; 72:19).'"[9]

The surah focuses on establishing the Qur'an as a divine source, and it warns of the fate of those who 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 yā sīn is the "heart of the Quran".[10] 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.[11] 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.[12] 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 the greatest and the last messenger of Allah to come.