John MacArthur, Éphésiens, Moody, 1986, p. 370.
The sword of the Spirit is first of all a defensive weapon, capable of deflecting the blows of an opponent. It is the believer’s supreme weapon of defense against the onslaughts of Satan. Unlike the shield, however, which gives broad and general protection, the sword can deflect an attack only if it is handled precisely and skillfully. It must parry the enemy weapon exactly where the thrust is made. When Jesus was tempted by Satan in the wilderness, His defense for each temptation was a passage of Scripture that precisely contradicted the devil’s word (Matt. 4:4, 7, 10). The Christian who does not know God’s Word well cannot use it well. Satan will invariably find out where we are ignorant or confused and attack us there. Scripture is not a broadsword (rhomphaia) to be waved indiscriminately, but a dagger to be used with great precision.
John MacArthur, Ephesians, Moody, 1986, p. 370.