Abdullah ibn Unays al-Juhani

ʿAbdullāh ibn Unays al-Juhanī was a Companion chosen by the Prophet (ﷺ) for a single-man mission to assassinate Khālid ibn Sufyān al-Hudhalī, chieftain of Hudhayl, who was gathering an army to attack Madinah after Uḥud (Muḥarram 4 AH). Having never seen Khālid, he asked the Prophet (ﷺ) for a description; the Prophet (ﷺ), relaying what he had been shown by revelation, told him he would know the man by the sheer terror his appearance would inspire. ʿAbdullāh set out alone with only his sword, found Khālid in the valley of ʿAranah exactly as described, ingratiated himself under false pretenses, and killed him when the moment allowed.

On the way, worried the time for prayer would lapse before he reached his target, he prayed while continuing to walk, gesturing with his head in place of the normal movements, an early instance of what later scholars classified as a form of ṣalāt al-khawf (the prayer of fear), and an example of Companions exercising ijtihād during the Prophet's (ﷺ) own lifetime. On his return, the Prophet (ﷺ) gifted him a staff and told him it would serve as a sign of recognition between them on the Day of Judgment. ʿAbdullāh kept the staff with him at all times for the rest of his life and left instructions that it be buried with him.