5:9 fruit Refers to natural results. Rooted in Christ, the believer’s life should produce Christlike virtues.
5:9 Fruit of light is similar to fruit of the Spirit (cf. Gal. 5:22–23).
5:9 fruit of the Light. This speaks of that which is produced by walking in the light (cf. 1Jn 1:5–7), namely moral excellence of heart, righteous behavior, and truthfulness (honesty or integrity). See notes on Gal 5:22, 23.
5:9. Paul describes one walking as a child of light as experiencing the fruit of the Spirit (cf. Gal 5:22–23; some manuscripts read the fruit of the light here), which is all goodness, righteousness, and truth.
Paul continues with his thought from Eph 5:8 as he commands believers to walk as children of light.
5:9 This parenthesis explains the type of fruit produced by those who walk in the light.
The fruit of the Spirit consists of all forms of goodness, righteousness, and truth. Goodness here is an inclusive term for all moral excellence. Righteousness means integrity in all dealings with God and men. Truth is honesty, equity, and reality. Put them all together and you have the light of a Christ-filled life shining out in a scene of dismal darkness.
9.—for the fruit of light (consists) in all goodness and righteousness and truth—. How does one know whether or not he is walking as a child of light? The answer is that light bears fruit, and this fruit will supply the needed evidence (Matt. 5:16; 7:20). The qualities of heart and life from which good works proceed are to be considered light, fruit. Paul mentions all goodness, a very general term, the opposite of “all malice” (4:31). Such goodness is Spirit-created moral and spiritual excellence of every description. Another way of looking at this goodness is to call it righteousness, the joy in doing what is right in the eyes of God, walking the straight path and never deviating from it. And still another description is truth: integrity, reliability, over against the sham, falseness, and hypocrisy that characterized the old way of life in which the Ephesians had formerly walked (4:14, 25; 5:6).
Ver. 9.—For the fruit of light is [shown] in all goodness and righteousness and truth. The exhortation is confirmed by this statement of what is the natural result of light—goodness, the disposition that leads to good works; righteousness, rectitude, or integrity, which is most careful against all disorder and injustice, and renders to all their due, and especially to God the things that are God’s; and truth, meaning a regard for truth in every form and way—believing it, reverencing it, speaking it, acting according to it, hoping and rejoicing in it, being sincere and honest, not false or treacherous.
9. fruit of the Spirit—taken by transcribers from Ga 5:22. The true reading is that of the oldest manuscripts, “The fruit of the light”; in contrast with “the unfruitful works of darkness” (Eph 5:11). This verse is parenthetic. Walk as children of light, that is, in all good works and words, “FOR the fruit of the light is [borne] in [Alford; but Bengel, ‘consists in’] all goodness [opposed to ‘malice,’ Eph 4:31], righteousness [opposed to ‘covetousness,’ Eph 5:3] and truth [opposed to ‘lying,’ Eph 4:25].”
5:9 / Just as a seed, plant, or tree fulfills its true nature by producing fruit, a believer, who is light in the Lord, will produce the virtues of goodness, righteousness and truth—quite the opposite of the fruit of darkness in 5:3, 5. By insisting on the moral implications of light, the author would be opposing any false theories, such as those in the Gnostic system, that made enlightenment a mystical experience and viewed the ethical life with indifference and even disdain. To be light is to walk in the light (John 3:19, 20; 1 John 1:5–7; 2:8–11).
The fruit of light is similar to the fruit of the Spirit mentioned in Galatians 5:22, although goodness is the only concept that occurs there. The items on this list are probably selected for their relevance to the theme of unity within the body of Christ. The virtues of goodness, righteousness, and truth are essential to healthy personal and social relationships.
9 The lives of children of light will yield the “fruit of light”—that is, “all goodness and righteousness and truth.” The fruit of light, in fact, is identical with the “fruit of the Spirit” in Gal. 5:22–23; it is not surprising that the latter reading has found its way into the text of Eph. 5:9 in many manuscripts (including the oldest extant Pauline manuscript). This ethical sense of “fruit” seems to be unknown to the Qumran writers.
Goodness, righteousness, and truth are basic moral qualities. Goodness belongs to the “fruit of the Spirit” in Gal. 5:22 where, as a specific virtue among others, it may mean something like “generosity”; but its range of meaning is as wide as that of the adjective “good.” One may think of the “good works” for which, according to Eph. 2:10, God has created his people in Christ Jesus; similarly Paul prays that the Colossians may “bear fruit in every good work” (Col. 1:10). As for righteousness, the “new man” has been described above as “created according to God in righteousness” (Eph. 4:24). Paul prays that his Philippian friends may be “filled with the fruit of righteousness” (Phil. 1:11), and the writer to the Hebrews speaks of discipline as yielding “the peaceful fruit of righteousness to those who have been trained by it” (Heb. 12:11). Truth is the antithesis of falsehood, which the readers have already been urged to “put off”; the truth of speech which they are exhorted to practice one with another (Eph. 4:25) should be the expression of that “truth in the inward being” which is divinely implanted in the children of light.
9 Confirming this analysis Paul inserts an explanatory parenthesis that illustrates the results or fruit (to mix the metaphor, as Paul does) of light (karpos tou phōtos). When people walk in the light, certain traits emerge—a positive triad instead of the sinful triads of vv. 3, 4, and 5 (which are “fruitless deeds of darkness,” v. 11). Again “all” (cf. 1:8, 21; 3:19; 4:2, 10, 19, 31; 5:3) modifies these fruit: they should be abundantly present. “Goodness” (agathōsynē, GK 20) may also mean “generosity” or “kindliness to others.” The Greek dikaiosynē (GK 1466), which here means “upright behavior” (cf. Ro 6:16, 18–20), not saving righteousness, has both personal and interpersonal applications—avoiding the evils just enumerated and showing justice toward others (cf. BDAG, 248). Finally, “truth” (alētheia, GK 237) here implies sincerity, dependability, and genuineness. Paul clearly depicts the corporate implications of the life lived in the light. It is a life that generates a positive impact on the lives of others.
 MacArthur, J. F., Jr. (2006). The MacArthur study Bible: New American Standard Bible. (Eph 5:9). Nashville, TN: Thomas Nelson Publishers.
 MacDonald, W. (1995). Believer’s Bible Commentary: Old and New Testaments. (A. Farstad, Ed.) (p. 1943). Nashville: Thomas Nelson.
 Jamieson, R., Fausset, A. R., & Brown, D. (1997). Commentary Critical and Explanatory on the Whole Bible (Vol. 2, p. 353). Oak Harbor, WA: Logos Research Systems, Inc.
 Bruce, F. F. (1984). The Epistles to the Colossians, to Philemon, and to the Ephesians (pp. 373–374). Grand Rapids, MI: Wm. B. Eerdmans Publishing Co.