Epheser 6:10

Finally - Having laid before you, your great and high calling, and all the doctrines and precepts of the Gospel, it is necessary that I should show you the enemies that will oppose you, and the strength which is requisite to enable you to repel them. Be strong in the Lord - You must have strength, and strength of a spiritual kind, and such strength too as the Lord himself can furnish; and you must have this strength through an indwelling God, the power of his might working in you.

my brethren--Some of the oldest manuscripts omit these words. Some with Vulgate retain them. The phrase occurs nowhere else in the Epistle (see, however, Eph 6:23); if genuine, it is appropriate here in the close of the Epistle, where he is urging his fellow soldiers to the good fight in the Christian armor. Most of the oldest manuscripts for "finally," read, "henceforward," or "from henceforth" (Gal 6:17). be strong--Greek, "be strengthened." in the power of his might--Christ's might: as in Eph 1:19, it is the Father's might.

Finally, my brethren,.... This is the conclusion of the apostle's exhortations, in which he addresses the saints as his brethren; which appellation he uses, not merely as a familiar way of speaking among the Jews, but in regard to them as regenerate persons, and of the same family and household of God with himself; and he calls them so, to show his humility, and as a proof of his affection to them, and with a design to encourage them to their duty, as follows: be strong in the Lord, and in the power of his might; which is directed to, partly on account of the things before exhorted to, which could not be performed in their own strength; and partly with respect to their many and potent enemies hereafter mentioned, against whom they had no might nor power of their own; and therefore the apostle points out the Lord Jesus Christ unto them, in whom are strength, power, and might, even everlasting strength, to enable them to perform their duty, and to fight against every enemy, sin, Satan, and the world; for though they are weak, and strength in themselves, and can do nothing of themselves, and without Christ; yet since there is strength in him, which is communicable to them, they may expect it from him, and depend upon it; and they may come at, or strengthen themselves in it, and by it, by meditation on it, by prayer for it, by waiting on Christ in his own ways, by exercising faith upon him, and through the Spirit, who strengthens them from him with might in the inward man.

Here is a general exhortation to constancy in our Christian course, and to encourage in our Christian warfare. Is not our life a warfare? It is so; for we struggle with the common calamities of human life. Is not our religion much more a warfare? It is so; for we struggle with the opposition of the powers of darkness, and with many enemies who would keep us from God and heaven. We have enemies to fight against, a captain to fight for, a banner to fight under, and certain rules of war by which we are to govern ourselves. "Finally, my brethren (Eph 6:10), it yet remains that you apply yourselves to your work and duty as Christian soldiers." Now it is requisite that a soldier be both stout-hearted and well armed. If Christians be soldiers of Jesus Christ, I. They must see that they be stout-hearted. This is prescribed here: Be strong in the Lord, etc. Those who have so many battles to fight, and who, in their way to heaven, must dispute every pass, with dint of sword, have need of a great deal of courage. Be strong therefore, strong for service, strong for suffering, strong for fighting. Let a soldier be ever so well armed without, if he have not within a good heart, his armour will stand him in little stead. Note, spiritual strength and courage are very necessary for our spiritual warfare. Be strong in the Lord, either in his cause and for his sake or rather in his strength. We have no sufficient strength of our own. Our natural courage is as perfect cowardice, and our natural strength as perfect weakness; but all our sufficiency is of God. In his strength we must go forth and go on. By the actings of faith, we must fetch in grace and help from heaven to enable us to do that which of ourselves we cannot do, in our Christian work and warfare. We should stir up ourselves to…

6:10-20 Paul’s final word is to remind the believers of the devil’s opposition and urge them to protect themselves with all of God’s armor.