“Wherefore be ye not unwise, but understanding what the will of the Lord is” (Ephesians 5:17).
The “wherefore” is preceded by the command: “walk as children of light” (Ephesians 5:8). This title, “Children of Light”, is used only three other times in the New Testament: once by the Lord Jesus to contrast worldly wisdom with the ineffectual use of godly wisdom in the “least things” (Luke 16:8); once again to direct us to “believe in the light” (John 12:36); and finally by Paul to encourage us to “watch and be sober” (I Thessalonians 5:5,6).
A “light-like” life, also called “the fruit of the Spirit,” is expressed in the character of “goodness” (Romans 15:14), “righteousness” (Romans 14:17,18), and “truth” (Ephesians 5:9; compare Galatians 5:22). In fact, the transformation of our character by our conscious choice to “present (our) bodies a living sacrifice, holy, acceptable unto God” enables us to “prove what is that good and acceptable, and perfect will of God” (Romans 12:1,2; Ephesians 5:10). An equation is clearly drawn between godly behavior and godly wisdom.
It therefore follows that children of light should “have no fellowship with the unfruitful works of darkness” (Ephesians 5:11), taking the responsibility to “reprove them” and recognizing the “shame even to speak of those things . . .” (Ephesians 5:12). The “light” things “make manifest” (present, display) that which is reproved enabling us to “walk circumspectly [accurately, carefully] not as fools but as wise” (Ephesians 5:15). That wisdom is not the foolish “wisdom of this world” (I Corinthians 1:20), but the “wisdom of God” (I Corinthians 2:7) that we might “know the things that are freely given to us of God” (I Corinthians 2:12), “understanding what the will of the Lord is.” HMM, III