1. The Prophet (SalAllahu alayhi wasalam) said, 'Surely everything has a heart, and the heart of the Qur'an is Yasin. I would love that it be in the heart of every person of my people'[Bazzar]. (S.Muhammad Ali Sabuni, Tafsir-al-SabuniVol.2)
2. The Prophet (SalAllahu alayhi wasalam) said, 'Whoever recites Yasin once Allah will record the reward of reciting the Qur'an ten times.'[Maqal, Tirmidhi 2812/A & Dhahabi]
3. It has been reported by Aisha (radiAllahu anha)that the Prophet (SalAllahu alayhi wasalam) said that there is a surah in the Qur'an that intercedes for itsreciter and forgive its listener. Know! It is Surah Yasin. It is called 'Mu'amma' in the Torah. It was enquired, what is Mu'amma? The Prophet (SalAllahu alayhi wasalam) said, 'it embraces the person with the goodness of this world and removes the dismay of the Hereafter'[Hashiya of Tafsir Jalalalayn, pg 368].
4. The Prophet said, 'Whoever recited Surah Yasin in the night seeking Allah's pleasure, Allah would forgive him'[Ibn Hibban, Darimi 3283/A, Abu Yala, Tabarani, Baihaqi & Ibn Mardawaih]
5. Ma`qil ibn Yasar (Allah be pleased with him) relates that the Messenger of Allah (Allah's blessings and peace be upon him, his family, companions, andfollowers) said,"Ya Sin is the heart of the Qur'an. No one reads it intending thereby Allah and the Next Abode except that Allah forgives them. Recite it for your deceased ones." [Related by Ahmad, Abu Dawud, Nasa'i (this wording is his), and Hakim, who deemed it rigorously authenticated (sahih)]
6. Imam Ghazali explained that this is because soundness of faith rests on acknowledging Resurrection and Judgment, and Surat Ya Sin details this in the most emphatic of ways. Imam Fakhr al-Din al-Razi concurred.
7. Imam Tibi explained in his commentary on Mishkat al-Masabih that Surat Ya Sin was called 'the Heart of the Qur 'an ' because of what it contains of overwhelming proofs, decisive signs, subtle spiritual meanings, eloquent admonition, and stern warnings.
Source: animals-and-shamanism.blogspot.com