[!~*AdOrAbLe*~!]

Ubayy bin Ka'b (radiAllahu anhu) reported:
The Messenger of Allah (peace be upon him) said: "Abu Mundhir!
Do you know which Ayah in Allah's Book is the greatest?
I said: 'Allah and His messenger know best.'
He (peace be upon him) again said:
'Do you know which Ayah in Allah's Book, according to you,
is the greatest?' I (Abu Mundhir) replied:
It is 'Allah la ilaha illa Huwal-Hayyul-Qayyum'.[2:255].
Thereupon he (peace be upon him) patted me in the chest and said,
' Rejoice by your knowledge, O Abu Mundhir!
(i.e, may this knowledge be a source of respect,
honour and benefit to you)'."

[Muslim]