Boyd’s Bible Dictionary:

Concise Bible Dictionary:

For the protection of the head, as worn by warriors. See ARMOR. In the Christian’s armor the helmet is “salvation,” or “the hope of salvation” (Eph. 6:1717And take the helmet of salvation, and the sword of the Spirit, which is the word of God: (Ephesians 6:17); 1 Thess. 5:88But let us, who are of the day, be sober, putting on the breastplate of faith and love; and for an helmet, the hope of salvation. (1 Thessalonians 5:8)). It is those who know their salvation that can take part against the wicked spirits in the heavenlies. It is to be remarked that Jehovah (Christ) in a future day will Himself put on righteousness as a breastplate, and a helmet of salvation, to avenge His people by punishing their enemies (Isa. 59:1717For he put on righteousness as a breastplate, and an helmet of salvation upon his head; and he put on the garments of vengeance for clothing, and was clad with zeal as a cloke. (Isaiah 59:17)).