Jamieson, Fausset and Brown on Ephesians 3:16

16. according to--that is in abundance consonant to the riches of His glory; not "according to" the narrowness of our hearts. Col 1:11, "Strengthened with all might according to His glorious power."

by--Greek, "through"; "by means of His Spirit."

in--The Greek implies, "infused into."

the inner man--(Ep 4:22, 24; 1Pe 3:4); "the hidden man of the heart." Not predicated of unbelievers, whose inward and outward man alike are carnal. But in believers, the "inner (new) man," their true self, stands in contrast to their old man, which is attached to them as a body of death daily being mortified, but not their true self.