Sūrah Yāʾ-Sīn 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, 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 PBUH, 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].'"