"Finally, my brethren, be strong in the Lord and in the power of His might" (Ephesians 6:10; NKJV).
Strong - to empower (Strong's).
In the Lord - describes a relationship
Power - vigor (Strong's); power, might (Thayer's).
Might - ability, force, strength (Thayer's).
Ephesians 6:10 describes the proper combination of divine enabling and human co-operation. The strength is the Lord's, and without "the power of His might" we shall be defeated, but we still must be "strong in the Lord and the power of His might." The verb is a passive present which could almost be rendered 'Strengthen yourselves in the Lord' (Ephesians, Stott, p. 266).
Jason Cicero