Jamieson, Fausset and Brown on Ephesians 1:19

19. exceeding--"surpassing."

power to us-ward who believe--The whole of the working of His grace, which He is carrying on, and will carry on, in us who believe. By the term "saints" (Ep 1:18), believers are regarded as absolutely perfected, and so as being God's inheritance; in this verse, as in the course of fighting the good fight of faith.

according to--in accordance with, what might be expected from.

working--Greek, "the energizing"; translate, "the effectual working" (Ep 3:7). The same superhuman power was needed and exerted to make us believe, as was needed and exerted to raise Christ from the dead (Ep 1:20). Compare Php 3:10, "the power of His resurrection" (Col 2:12; 1Pe 1:3-5).

of his mighty power--Greek, "of the strength of His might."