Charles Ellicott Commentary Ephesians 5:17

"Wherefore be ye not foolish, but understand what the will of the Lord is." — Ephesians 5:17 (ASV)

Be you not unwise.—The word here is stronger than in Ephesians 5:15; it is properly senseless, used of "the fool" (Luke 11:40; Luke 12:20; 1 Corinthians 15:36; 2 Corinthians 11:16, 19; 2 Corinthians 12:6, 11). By it St. Paul emphasizes his previous warning; then he adds the explanation that to be "wise" is to understand what the will of the Lord is—to know His purpose towards us and towards the world, and so to know the true purpose of our life. Hence we are told in Job 28:28, that the fear of the Lord is wisdom, or, more precisely, in Proverbs 9:10, that it is the beginning of wisdom.