(70) باب الْحِرَاسَةِ فِي الْغَزْوِ فِي سَبِيلِ اللَّهِ
Narrated `Aisha:
The Prophet (ﷺ) was vigilant one night and when he reached Medina, he said, "Would that a pious man from my companions guard me tonight!" Suddenly we heard the clatter of arms. He said, "Who is that? " He (The new comer) replied, " I am Sa`d bin Abi Waqqas and have come to guard you." So, the Prophet (ﷺ) slept (that night).
Reference: Sahih al-Bukhari 2885
In-book reference: Book 56, Hadith 100
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 136