Which verse is the heart of Surah Ya-Sin?

As it is relatively considered as a famous issue (that Surah Ya-sin is the heart of Quran), and as a narration, it is quoted that Imam Sadiq (a.s.) said: > Everything has a heart, and surah Ya-Sin is the heart of the Quran. > > صدوق، محمد بن على‏، ثواب الاعمال و عقاب الأعمال So, I was wondering which verse of Surah Ya-Sin is considered as the heart of this Surah.