Guarding Rasulullah (sallallahu ‘alaihi wasallam):

Hazrat ‘Aa’ishah (radhiyallahu ‘anha) narrates:

After migrating to Madinah Munawwarah, on one occasion, Rasulullah (sallallahu ‘alaihi wasallam) could not fall asleep during the night (out of fear that the enemy would attack him). It was then that Rasulullah (sallallahu ‘alaihi wasallam) said, “If only there was a pious person to guard me tonight.” While we were in that condition, we heard the sound of weapons. Rasulullah (sallallahu ‘alaihi wasallam) asked, “Who is there?” The person replied, “Sa’d bin Abi Waqqaas (radhiyallahu ‘anhu).” Rasulullah (sallallahu ‘alaihi wasallam) asked him, “What has brought you here?” Hazrat Sa’d (radhiyallahu ‘anhu) replied, “I feared for your life, O Rasulullah (sallallahu ‘alaihi wasallam), and so I have come to guard you.” Hearing this, Rasulullah (sallallahu ‘alaihi wasallam) made du‘aa for him and thereafter fell asleep.

(Sunan Tirmizi #3756, Fat-hul Baari 6/96)