Ephesians 6:17

And take the helmet of salvation
Meaning either Christ himself, the Saviour; and so the Arabic version renders it, "the helmet of the Saviour": or the salvation itself, which he is the author of, and a well grounded hope of it; see ( 1 Thessalonians 5:8 ) ; the allusion is to ( Isaiah 59:17 ) ; and such an hope of salvation by Christ is a defence of the head against false doctrines; for the helmet is a piece of armour for the head; and it is an erecter of the head in times of difficulty, affliction, and distress; and it covers the head in the day of battle, when engaged with Satan, the enemy of souls:

and the sword of the Spirit, which is the word of God;
the word of God is compared to a "sword", for its two edges, the law and Gospel; the one convicts of sin, and cuts to the heart for it, and the other cuts down all the goodliness of man; and the Scriptures in general are a sharp sword, in convincing of sin, reproving for it, and threatening with wrath and ruin, in refuting error and heresy, and repelling Satan's temptations, and will be used in the destruction of antichrist: and this word may be called "the sword of the Spirit", because it is not carnal, but of a spiritual nature; and is used by the spiritual man; and because the Holy Spirit, as the Ethiopic version here expresses it, is the author of it; and which he furnishes the saints with, and teaches them how to make use of, and makes it powerful and effectual. So the Jews say ^F20, the words of the law are like to a sword, and speak of (hrwt brx) "the sword of the law" ^F21