They all hold swords, being expert in war: every man hath his sword upon his thigh because of fear in the night.
They all hold swords - not actually grasping them, but having them "girt on the thigh" ready for use, like their Lord. So believers, too, are guarded by angels (Hebrews 1:14), and they themselves need "every man" (Nehemiah 4:18) to be armed (Ephesians 6:12; Ephesians 6:17).
Expert in war - (2 Corinthians 2:11.)
Because of fear in the night. Arab marauders often turn a wedding into mourning by a night attack. So the bridal procession of saints in the night of this wilderness is the chief object of Satan's assault.