We are beginning to see that discernment was a significant category for Paul. As an apostle, Paul was very much accustomed to giving the Lord Jesus Christ’s divine instruction to the church for doctrine, worship, and practice. But he was also very much aware that such instruction could in no way satisfy all the moral decisions required of Christians. Therefore he prayed the Philippian church (Phil 1:9-11) would use discernment to approve what is excellent (part 1). He told the Roman believers (Rom 12:1-2) that their renewed minds were to be used to prove the good, acceptable, and perfect will of God (part 2). He even prayed that the Colossian believers (Col 1:9-10), whom he had never met, would understand God’s will (i.e., what God wanted them to do at certain moral crossroads) with spiritual wisdom (part 3). The Thessalonian Christians (1 Thess 5:19-24) were told to test, not only prophecies, but all things, clinging to what was good and abhorring every form of evil (part 4).
Paul provided similar instructions for the Ephesian Christians as well. The text before us in this installment is Eph 5:7-11.
 Therefore do not become partners with them;  for at one time you were darkness, but now you are light in the Lord. Walk as children of light  (for the fruit of light is found in all that is good and right and true),  and try to discern what is pleasing to the Lord.  Take no part in the unfruitful works of darkness, but instead expose them.
In the verses preceding, Paul calls the Ephesians to shun all carnal, fleshly, sinful living. It is because of such sins that “the wrath of God comes upon the sons of disobedience” (v6). Therefore, we should not be partners with them in their crimes. Such sins should be far from us. It is true that the Ephesians used to live in such sins: “for at one time you were darkness,” but they have been changed by Jesus Christ: “now you are light in the Lord.” The two indicatives speak to the change: “at one time you were . . . but now you are.” The truth of their union with Christ has changed them and put them in a new realm, the realm of light in the Lord.
The darkness/light metaphor is a fitting one for our spiritual life (or lack thereof). In a place of darkness, you cannot see where you are going. You stumble about. You don’t understand the world around you. You misuse things because you cannot see what they are. So is everyone who is apart from Christ. They are tripping around in the shadowlands, unable to determine what things really are, what reality truly is, or how things ought to be used and considered. By contrast, the children of light know that this world is nothing but vanity, that a better reality is coming, the daystar has come, and light is about to break forth at the return of Christ (cf. 2 Pet 1:19-20). And, given the fact that we are now “light in the Lord,” so we should “walk as children of light.” The indicative is turned into an imperative.
What marks the light-people are fruits of the life of the future: “all that is good and right and true.” Again, Paul has ethical or moral matters in view here (cf Phil 1:9-11; 4:8-9). There is a way of living that reflects all that the claims of the Christian life upon an individual, and this is a life of goodness and righteousness and truth. This is living in accordance with reality, with light, with the truth.
It is well represented in several versions that verse 10 is a kind of parenthetical remark explaining what it means that we walk as children of light. But Paul adds a qualifying participle to our walking as children of light. “Walking as children of light” requires more from us than simply a passive hope for moral goodness. Indeed, alongside our walking, we must be “testing” what is “pleasing to the Lord.” Behind the words translated in the ESV “try to discern” is the word δοκιμάζοντες. If you’ve been following along in this series, you will immediately recognize this verb as behind the other passages we have studied at this point (except Col 1:9-10). I think “try to discern” is an unfortunate translation (the ESV echoes the RSV translation exactly). We might better translate 8b and 10, “Walk as children of light, . . . discerning what is pleasing to the Lord” (cf. HCSB). There is no hint of “try” in the sense of “attempt” in the verse. If we take the word translated in the ESV “try” in the sense of “test,” the translation is good, for that well represents the idea.1 We are to test the ethical questions before us and make a discerning decision as to what pleases the Lord based on that testing. So, in order for us to walk as children of light, we must be people who are actively using discernment in the moral decisions we face in the world.
The command to use discernment concerning what is good and evil leads naturally into verse 11: “Take no part in the unfruitful works of darkness, but instead expose them.” Through testing we are able to do just that, expose the foolish practices of the darkened world. Paul continues his commands along these lines (the study of which, though fruitful, exceeds our present scope).
So we have here another call to discernment. Andrew Lincoln notes that the verb δοκιμάζω was “an important term in Stoic ethics, where the testing was in accordance with reason.”2 What sets Paul’s ethics apart is that this testing flows not out of reason as much as the light of the Lord and our union with him. This illumination, of course, comes most pointedly from the Word of Christ. As we learn of Christ the Word in the Holy Scriptures, so we are better able to discern what is pleasing to God. It is unfathomable that such reasoning should take place outside the foundation laid by Scripture. Indeed, the moral imperatives of Scripture are the surest and safest way of beginning to know what is pleasing to God. At the same, verse 10 is a frank call for us to use our own Word-enlightened discernment to test and approve what is around us as to whether or not it pleases the Lord. Frank Thielman is correct when he comments,
Here [δοκιμάζω] refers to the believer’s use of critical judgment to ‘find out’ (NRSV) in any given situation what he or she should do.3
This approach to ethics seems to have been a studied aspect of Paul’s theological convictions. Although he certainly handed on to those under his pastoral care a set body of ethical teaching (4:21-24; cf. 1 Thess. 4:1; 2 Thess. 2:15; 3:6; 1 Cor. 4:17; Rom. 6:17), he also intentionally left room for believers to make decisions by using their own renewed thinking.4
In some ways this echoes Lincoln. He says that while the Jewish Qumran based ethics strictly on the Mosaic Law,
Paul holds that believers are able to discover the will of God in the concrete situations they face, as they place their whole beings at God’s disposal.5
Lincoln cites Cullman, who makes “testing” the “key” to Christian ethics in the New Testament.6
It might helpful by way of reminder that we began this series noting the strange understanding of discernment by one of the darlings of the “Young, Restless, and Reformed” movement. Indeed, the contemporary American evangelical church is woefully undiscerning. A kind of strict letter-of-the-law legalism renders nearly every moral matter adiaphora. ((In our opinion, this legalism is more often than not used as a license for liberty to engage in otherwise carnal, fleshly living. But we do not even concede the point that most of the moral matters in question are not addressed by Scripture when the implications of the plain moral indicatives are seriously considered.)) What we are establishing in this series that there is a serious biblical call for us to exercise, upon the foundation of the Word of God, discernment in ethical and moral decisions. Paul did not desire or expect every single moral imperative to come from Scripture alone; indeed, he wanted his new churches to use a discernment saturated by apostolic teaching to make tough moral decisions in their own age. If we render all moral and ethical decisions not explicitly addressed in Scripture as immaterial, unimportant, or indifferent, then we ourselves not following an explicit command of Scripture to exercise discernment concerning moral and ethical decisions. Yes, it is a command of our Lord’s apostles that we, as people illumined by the Word of Christ, test our world and approve what is pleasing to God.
This series is still not finished, but it should be noted that the importance of discernment has special relevance to us with respect to worship. We believe that the decisions each church makes regarding what it sings, how it sings, how it prays, and how it preaches, are matters that are both explicitly addressed in Scripture as well as requiring discernment as to how to apply the plain statements of Scripture. Discernment is needed by Christian leaders, not only in ordinary, everyday ethical decisions, but in how we go about being and acting as the church of Christ assembled for worship.