Narrated Sahl ibn al-Hanzaliyyah: The iqamah for the morning prayer was pronounced and the Messenger of Allah (ﷺ) began to offer prayer while he was looking at the mountain-pass. (AbuDawud elaborated that the Prophet had sent a horseman to the mountain-pass at night in order to keep watch)
SahihSahihIsnaad HasanBook 2 · Hadith 527