Ayat Al-Kursi
Question :
Why is Ayat Al-Kursi the greatest verse in the Qur'an?
Answer:
Ayat Al-Kursi mentions, both explicitly and implicitly, many of Allah's attributes; singling Him out in worship, and those qualities of perfection that befit Allâh Almighty, and negating those qualities of imperfection that do not befit Him Almighty. In no other verse of the Qur'an are these qualities found to the same degree, which is why its virtues are extolled in many Hadiths, and which is why it is to be recited after the obligatory prayers, before going to sleep, and why it helps to repel Shaytan, along with the other great benefits mentioned with reciting it.
Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 7 Page 18