All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, you should know that the Prophetic narration which reads “Yaseen is the heart of the Quran.” is weak, and it was reported by Imaam Ahmad and others .
As regards the reason why this chapter is called the heart of the Quran, the scholars stated that it is because it contains many great matters concerning confirming the Oneness of Allaah, the Resurrection, the Recompense, and so forth, so it is like a heart in its importance compared to other limbs of the body.