8 For you were heretofore darkness, but now light in the Lord. Walk then as children of the light.
9 For the fruit of the light is in all goodness and justice and truth:
10 Proving what is well pleasing to God.
11 And have no fellowship with the unfruitful works of darkness: but rather reprove them.
12 For the things that are done by them in secret, it is a shame even to speak of.
(8) You were once in the darkness of Gentile error, and so far might have found some excuse; but you are now enlightened by the faith and grace of Christ. Walk therefore as sons of light, making it your object to study, examine, cherish, and carry out in practice, that which is the will of God concerning you. (9) For the fruit of light, the outcome of the faith of Christ, is goodness, justice, truth, in opposition to the fruit of darkness, wrath, fraud, or avarice, and lies, referred to above (Eph 4:31). The fruit of the sunshine is the ripened grape, the growth of the dark dungeon the poisonous fungus. The Greek text has, the fruit of the Spirit. (11) Hold no communication with the fruitless works of darkness. Do not do them, do not praise them, do not approve them, do not consent to others doing them, do not jest at them, do not speak of them, do not think of them. Fruitless, because they have no fruit of life eternal; their fruit is death. Rather reprove them, by taking no part in them, or, if necessary, protesting in words. For it is not sufficient to do well, if we tolerate and encourage, by flattery, complacence, or approval, the evil deeds of others. (12) What these people do in their secret assemblies, is execrable even to be said. So the Syriac. St. Epiphanius says that this refers to the heretical followers of Simon Magus.
13 But all things that are reproved are made manifest by the light: for all that is made manifest is light.
14 Wherefore he saith: Rise, thou that sleepest, and arise from the dead: and Christ shall enlighten thee.
The Syriac of verse 13 has: All things are by light proved and revealed. The right way to reprove the darkness of evil, is by the light of good deeds; because it is the nature of light to illumine. The light of day brings into prominence all that had been hidden in the shades of night; so do good deeds bring out by contrast the evil deeds of others. As Christ, who is the Light of the world, illumines every man who comes into the world, so in proportion the Christian, who is a son of this Light, should illumine and enlighten his neighbour by his good deeds and his example. For a holy life is a light which is not only conspicuous in itself, but sheds its radiance on, and is reflected from, all the objects around. The quotation in verse 14, as St. Thomas thinks, is from Isaiah 60:1. Rise, be enlightened, Jerusalem, for thy light is come. Thy light is Christ. Other writers think the words are taken from some other canonical book, which has been lost: they do not occur in the Scriptures literally as the Apostle gives them.