Abu `Isa At-Tirmidhi recorded from Ibn `Abbas that Abu Bakr said, "O Messenger of Allah, verily your hair has turned gray.'' The Prophet replied,
(Surahs Hud, Al-Waqi`ah, Al-Mursalat, `Amma Yatasa'lun ﴿An-Naba'﴾ and Idhash-Shamsu Kuwwirat ﴿At-Takwir﴾ have turned my hair gray.) In another narration he said,
(Surah Hud and its sisters...)
In the Name of Allah, the Most Gracious, the Most Merciful.