Clarke's Commentary on the Bible
Wherefore - Because ye have such enemies to contend with, take unto you - assume, as provided and prepared for you, the whole armor of God; which armor if you put on and use, you shall be both invulnerable and immortal. The ancient heroes are fabled to have had armor sent to them by the gods; and even the great armor-maker, Vulcan, was reputed to be a god himself. This was fable: What Paul speaks of is reality.
That ye may be able to withstand - That ye may not only stand fast in the liberty where with Christ hath made you free, but also discomfit all your spiritual foes; and continuing in your ranks, maintain your ground against them, never putting off your armor, but standing always ready prepared to repel any new attack.
And having done all, to stand - Και ἁπαντα κατεργασαμενοι στηναι· rather, And having conquered all, stand: this is a military phrase, and is repeatedly used in this sense by the best Greek writers. So Dionys. Hal. Ant., lib. vi., page 400: Και παντα πολεμια εν ολιγῳ κατεργασαμενοι χρονῳ· "Having in a short time discomfited all our enemies, we returned with numerous captives and much spoil." See many examples in Kypke. By evil day we may understand any time of trouble, affliction, and sore temptation.
As there is here allusion to some of the most important parts of the Grecian armor, I shall give a short account of the whole. It consisted properly of two sorts:
1. Defensive armor, or that which protected themselves.
2. Offensive armor, or that by which they injured their enemies. The apostle refers to both.
I. Defensive Armor
Περικεφαλαια, the Helmet; this was the armor for the head, and was of various forms, and embossed with a great variety of figures. Connected with the helmet was the crest or ridge on the top of the helmet, adorned with several emblematic figures; some for ornament, some to strike terror. For crests on ancient helmets we often see the winged lion, the griffin, chimera, etc. St. Paul seems to refer to one which had an emblematical representation of hope.
Ζωμα, the Girdle; this went about the loins, and served to brace the armor tight to the body, and to support daggers, short swords, and such like weapons, which were frequently stuck in it. This kind of girdle is in general use among the Asiatic nations to the present day.
Θωραξ, the Breast-Plate; this consisted of two parts, called πτερυγες or wings: one covered the whole region of the thorax or breast, in which the principal viscera of life are contained; and the other covered the back, as far down as the front part extended.
Κνημιδες, Greaves or brazen boots, which covered the shin or front of the leg; a kind of solea was often used, which covered the sole, and laced about the instep, and prevented the foot from being wounded by rugged ways, thorns, stones, etc.
Χειριδες, Gauntlets; a kind of gloves that served to defend the hands, and the arm up to the elbow.
Ασπις, the clypeus or Shield; it was perfectly round, and sometimes made of wood, covered with bullocks' hides; but often made of metal. The aspis or shield of Achilles, made by Vulcan, was composed of five plates, two of brass, two of tin, and one of gold; so Homer, Il. U. v. 270: -