Why did the chapter of Hoode make the Prophet's hair go grey?

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, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said that the chapter of Hoode (11th chapter of Quran) made his hair go grey. At-Tirmithi narrated this Hadeeth on the authority of Ibn ‘Abbaas and this Hadeeth is Saheeh.

Al-Munaawi explained that when the Prophet, sallallaahu ‘alayhi wa sallam, read in the chapter Hoode about the horrors experienced by previous nations, his hair went grey for fear that his nation might experience such horrors. 

Allaah Knows best.