“Finally, my brethren, be strong in the Lord, and in the power of his might.”
King James Version (KJV)
6:10 Brethren - This is the only place in this epistle where he uses this compellation. Soldiers frequently use it to each other in the field. Be strong - Nothing less will suffice for such a fight: to be weak, and remain so, is the way to perish. In the power of his might - A very uncommon expression, plainly denoting what great assistance we need as if his might would not do, it must be the powerful exertion of his might.
Eph 6:10 Be strong in the Lord. He comes to his final admonition. They are engaged in a fearful warfare (Eph 6:12). They need to be equipped for it. Let them "be strong" by using the armor, weapons and means which are named in the next section.