The Greek verb anazonnymi means "to gird up" — specifically to gird up one's loins, the ancient gesture of gathering long robes and tucking them in the belt to allow free movement. It appears once in the New Testament in 1 Peter 1:13.
Peter's command to "gird up the loins of your mind" in 1 Peter 1:13 is a vivid call to mental readiness and disciplined hope. As a soldier would gather robes for action, believers must gather wandering thoughts and focus them on the hope of Christ's return. Mental discipline is a spiritual discipline. The resurrection hope should produce not passive waiting but active, alert, purposeful living.