Helmet. A military headgear designed to protect a fighter during battle and a very basic part of defensive armor. The Hebrew word for “helmet” is koh·vaʽʹ (alternately qoh·vaʽʹ), while the Greek term is pe·ri·ke·pha·laiʹa, literally meaning “around the head.”​—1Sa 17:5, 38; Eph 6:17.

As a helmet protects a soldier’s head, so “the helmet of salvation” safeguards the Christian’s mental powers from ungodly influences. (Eph 6:17) Having on “as a helmet the hope of salvation” means looking “intently toward the payment of the reward,” as Moses did.​—1Th 5:8; Heb 11:26.

“The sword of the spirit, that is, God’s word” is indispensable to the Christian in warding off false teachings and traditions of men and in teaching the truth and ‘overturning strongly entrenched things.’​—Eph 6:17; 2Co 10:4, 5.