God’s Will (15-17): We view life as an opportunity to positively carry out “the will of the Lord” (5:17). But this is no easy task, because there is a riptide of “evil” that is ever trying to drag us away into sin. Only fools just go with the flow and think they’ll be safe. Not so the wise. They watch their lives with a sharp eye, guarding against the evil from which Christ saved us. Also, we stay on the offensive. We understand God’s will and keep it fresh in our minds, because we don’t wish to squander our lives. God saved us and created us anew (2:10) with a passion to please the Lord (5:10), and Christ Himself is shining on us (5:14). How can we drift along as if rudderless? We are to lock into our God-given target: bear the fruit of light and expose unfruitful deeds.
The Spirit (18): Intoxication of all kinds dulls our senses to the will of God, and drives out wisdom (Prov. 20:1; 31:4-5). We are to eliminate from our lives all such mind-numbing devices. Instead, we position ourselves for the Spirit to fill us with the knowledge of His will. As alcohol inebriates when one imbibes, so the Spirit fills us when we are yielded to Him and attentive to His words. It is sheer foolishness to expect the Spirit to fill us when we remain rebellious and oblivious to His words. Be willing participants and the Spirit will fill you!
 “Time [kai-ros (καιρός)]” here is time as opportunity, not as chronological moments (chro-nos [χρόνος]). Hence, “making the most of your time” is to use life as an opportunity for God’s glory and His revealed will.
 “Because the days are evil” echoes the argument (“therefore”) and points to the danger of sin (4:17; 5:7, 11).
 The imperative of 5:15 is literally “watch carefully [a-kri-bōs (ἀκριβῶς)],” that is, with accuracy/exactness.
 “Understand” is imperfective, an ongoing practice, not merely an acknowledgement, but an assimilation.
 Cf. 5:9, 11. This in other words is sanctification (1:4; 2:21; 4:24) and outreach/evangelism (4:11; Col. 4:5-6).
 God’s will is that we be sober/alert (6:18; 1 Thes. 5:6; 1 Pet. 5:8). Wine is just of one many intoxicants.
 “Filled with the Spirit” means that the Spirit fills us with something, not that the Spirit is the content of filling. In this context, the content of His filling is the knowledge of God’s will (5:10, 17; cf. also Col. 1:9).
 Scripture clarifies how we are to respond to the Spirit: Acts 7:51; Rom. 8:5, 14; Gal. 5:16, 25; 6:8.