Charles Hodge on Ephesians 5:10

V. 10. Verse 9 is a parenthesis, as the 10th verse is grammatically connected with the 8th. "Walk as children of the light, proving, &c.," περιπατεῖτε—δοκιμάζοντες. Δοκιμάζειν is to try, to put to the test, to examine; then to judge or estimate; and then to approve. Thus it is said, "The fire shall try every man’s work;" God is said "To try the heart;" we are said "To be renewed so as to prove the will of God," Rom. 12, 2, that is, to examine and determine what the will of God is. And so in this passage believers are required to walk as children of light, examining and determining what is acceptable to the Lord. They are to regulate their conduct by a regard to what is well pleasing to Him. That is the ultimate standard of judging whether any thing is right or wrong, worthy or unworthy of those who have been enlightened from above.

The word LORD is in the New Testament so predominantly used to designate the Lord Jesus Christ, that it is always to be referred to him unless the context forbids it. Here the context so far from forbidding, requires such reference. For in the former part of the sentence Lord evidently designates Christ. "Ye are light in the Lord, therefore, walk as children of the light, proving what is acceptable to the Lord." This, therefore, is one of the numerous passages in the New Testament, in which Christ is recognized as the Lord of the conscience, whose will is to us the ultimate standard of right and wrong, and to whom we are responsible for all our inward and outward acts. It is thus that the sacred writers show that Christ was their God, in whose presence they constantly lived, whose favour they constantly sought, and on whom all their religious affections terminated. He was not merely the God of their theology, but of their religion.