The following is an excerpt from The MacArthur New Testament Commentary on Ephesians 6.

Stand firm therefore, having girded your loins with truth, (6:14a)The Roman soldier always wore a tunic, an outer garment that served as his primary clothing. It was usually made of a large, square piece of material with holes cut out for the head and arms. Ordinarily it draped loosely over most of the soldier’s body. Since the greatest part of ancient combat was hand–to–hand, a loose tunic was a potential hindrance and even a danger. Before a battle it was therefore carefully cinched up and tucked into the heavy leather belt that girded the soldier’s loins.

The ordinary citizen of the Near East had a similar problem with his robe. When he was in a hurry or had heavy work to do, he either took the robe off or tucked it around his waist. As God prepared the children of Israel to eat the Passover meal before they left Egypt, He instructed Moses to tell them, “Now you shall eat it in this manner: with your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it in haste” (Ex. 12:11). Concerning His second coming, Jesus tells us to “be dressed in readiness” (Luke 12:35), which is literally, “have your loins girded.” Peter used the same expression when he said, “Therefore, gird your minds [lit., “gird up the loins of your minds”] for action, keep sober in spirit, fix your hope completely on the grace to be brought to you at the revelation of Jesus Christ” (1 Pet. 1:13). Girding the loins was a mark of preparedness, and the soldier who was serious about fighting was sure to secure his tunic with his belt.

The belt that girded it all securely together and demonstrates the believer’s readiness for war is truth. Aletheia (truth) basically refers to the content of that which is true. The content of God’s truth is absolutely essential for the believer in his battle against the schemes of Satan. Without knowledge of biblical teaching, he is, as the apostle has already pointed out, subject to being “carried about by every wind of doctrine, by the trickery of men, by craftiness in deceitful scheming” (4:14). In his first letter to Timothy, Paul warns that “the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons” (1 Tim. 4:1). The “doctrines of demons” taught by cults and false religions have their origin in the “deceitful spirits” that in Ephesians Paul calls “rulers, … powers, … world forces of this darkness, … [and] spiritual forces of wickedness in the heavenly places” (6:12). These false schemes of Satan can be successfully encountered only with the truth of the Word of God.

But aletheia (truth) can also refer to the attitude of truthfulness. It represents not only the accuracy of specific truths but the quality of truthfulness. That seems to be the primary meaning Paul has in mind here. The Christian is to gird himself in an attitude of total truthfulness. To be girded … with truth therefore shows an attitude of readiness and of genuine commitment. It is the mark of the sincere believer who forsakes hypocrisy and sham. Every encumbrance that might hinder his work for the Lord is gathered and tucked into his belt of truthfulness so that it will be out the way. Just as the serious runner takes off every unnecessary piece of clothing before the race (Heb. 12:1), the serious soldier tucks in every loose piece of clothing before the battle.

How much more important is the Christian’s preparedness as he faces the forces of Satan. “No soldier in active service,” Paul says, “entangles himself in the affairs of everyday life, so that he may please the one who enlisted him as a soldier” (2 Tim. 2:4). It is sad that so many Christians are content to let the “tunics” of their daily cares and concerns flap in the breeze around them—continually interfering with their faithfulness to the Lord and giving the devil every opportunity to entangle and defeat them with their own immature habits and interests.

I believe that being girded … with truth primarily has to do with the self–discipline of total commitment. It is the committed Christian, just as it is the committed soldier and the committed athlete, who is prepared. Winning in war and in sports is often said to be the direct result of desire that leads to careful preparation and maximum effort. It is the army or the team who wants most to win who is most likely to do so—even against great odds.

Some years ago I was told of a young Jewish man from the United States who decided to go to Israel and live. After working there for two years he was required either to serve in the army for a given period of time or to return home. He decided to join the army. His father was a good friend of an Israeli general, who at first was afraid the young man would use that friendship to secure an easy, safe assignment. Instead, he went to the general and said, “My present duty is too easy. I want to be in the finest, most strategic, diligent, and difficult regiment in the Israeli army.” Commenting on that spirit of dedication, the general said, “People think Israelis are so successful at war because we are a super people or that we have super intellect or super strength. But our success is not built on any of those things; it is built on commitment, unreserved and sacrificial commitment.”

If athletes so dedicate and discipline themselves in order to possibly win a race and receive “a perishable wreath” from the world, how much more should believers in Jesus Christ dedicate and discipline themselves to absolutely win in their struggle against Satan and receive an “imperishable” wreath from God (1 Cor. 9:25)?

Being girded … with truth is being renewed in the mind, in order to “prove what the will of God is, that which is good and acceptable and perfect” (Rom. 12:2). When the mind is renewed in commitment to God’s truth, there is empowerment for the Christian soldier to become “a living and holy sacrifice” that please God and is that believer’s “spiritual service of worship” (v. 1). In many ways it is more difficult and more demanding to be a living sacrifice than a dying one. To be burned at the stake for one’s faith would be painful, but it would soon be over. To live a lifetime of faithful obedience can also be painful at times, and its demands go on and on. It requires staying power that only continual and total commitment to the Lord can provide. It demands that love “abound still more and more in real knowledge and all discernment, so that [we] may approve the things that are excellent, in order to be sincere and blameless until the day of Christ; having been filled with the fruit of righteousness which comes through Jesus Christ, to the glory and praise of God” (Phil. 1:9–11). Love, knowledge, and understanding of God all need to grow in us. And when those grow, so does our commitment to the Lord for excellence in all things—the ultimate goal of which is “the glory and praise of God.”

To be content with mediocrity, lethargy, indifference, and half–heartedness is to fail to be armored with the belt of God’s truth and to leave oneself exposed to Satan’s schemes.

John Monsell’s hymn focuses on the virtue of true commitment:    Fight the good fight with all thy might;
    Christ is thy strength, and Christ thy right.
    Lay hold on life, and it shall be
    Thy joy and crown eternally.    Run the straight race through God’s good grace,
    Lift up thine eyes, and seek His face;
    Life with its way before thee lies,
    Christ is the path, and Christ the prize.    Cast care aside, lean on thy Guide;
    His boundless mercy will provide;
    Trust, and thy trusting soul shall prove
    Christ is its life, and Christ its love.