Charles Hodge on Ephesians 6:14

V. 14. With the flowing garments of the East, the first thing to be done in preparing for any active work, was to gird the loins. The apostle therefore says, στῆτε οὖν περιζωσάμενοι τὴν ὀσφὺν ὑμῶν ἐν ἀληθείᾳ, stand therefore having your loins girt about with truth. By truth, here is not to be understood divine truth as objectively revealed, i. e. the word of God; for that is mentioned in the following verse as the sword. Nor does it mean sincerity of mind, for that is a natural virtue, and does not belong to the armour of God; which according to the context consists of supernatural gifts and graces. But it means truth subjectively considered; that is, the knowledge and belief of the truth. This is the first and indispensable qualification for a Christian soldier. To enter on this spiritual conflict ignorant or doubting, would be to enter battle blind and lame. As the girdle gives strength and freedom of action, and therefore confidence, so does the truth when spiritually apprehended and believed. Let not any one imagine that he is prepared to withstand the assaults of the powers of darkness, if his mind is stored with his own theories or with the speculations of other men. Nothing but the truth of God clearly understood and cordially embraced will enable him to keep his feet for a moment, before these celestial potentates. Reason, tradition, speculative conviction, dead orthodoxy, are a girdle of spider-webs. They give way at the first onset. Truth alone, as abiding in the mind in the form of divine knowledge, can give strength or confidence even in the ordinary conflicts of the Christian life, much more in any really "evil day."

Καὶ ἐνδυσάμενοι τὸν θώρακα τῆς δικαιοσύνης, and having put on the breast-plate of righteousness. The θώραξ was the "armour covering the body from the neck to the thighs, consisting of two parts, one covering the front and the other the back." A warrior without his θώραξ was naked, exposed to every thrust of his enemy, and even to every casual dart. In such a state flight or death is inevitable. What is that righteousness, which in the spiritual armour answers to the cuirass? Many say it is our own righteousness, integrity, or rectitude of mind. But this is no protection. It cannot resist the accusations of conscience, the whispers of despondency, the power of temptation, much less the severity of the law, or the assaults of Satan. What Paul desired for himself was not to have on his own righteousness, but the righteousness which is of God by faith; Phil. 3, 8. 9. And this, doubtless, is the righteousness which he here urges believers to put on as a breast-plate. It is an infinitely perfect righteousness, consisting in the obedience and sufferings of the Son of God, which satisfies all the demands of the divine law and justice; and which is a sure defence against all assaults whether from within or from without. As in no case in this connection does the apostle refer to any merely moral virtue as constituting the armour of the Christian, so neither does he here. This is the less probable, inasmuch as righteousness in the subjective sense, is included in the idea expressed by the word truth in the preceding clause. It is the spirit of the context which determines the meaning to be put on the terms here used. For although righteousness is used so frequently by the apostle for the righteousness of God by faith, yet in itself it may of course express personal rectitude or justice. In Is. 59, 17, Jehovah is described as putting "on righteousness as a breast-plate, and a helmet of salvation on his head;" as in Is. 11, 5, it is said of the Messiah, "righteousness shall be the girdle of his loins, and faithfulness the girdle of his reins."