The phrase occurs only here and in 1Jo 1:6. Note the contrasted phrase, doeth evil (Joh 3:20). There the plural is used: doeth evil things; evil being represented by a number of bad works. Here the singular, the truth, or truth; truth being regarded as one, and “including in a supreme unity all right deeds.” There is also to be noted the different words for doing in these two verses: doeth evil (πράσσων); doeth truth (ποιῶν). The latter verb contemplates the object and end of action; the former the means, with the idea of continuity and repetition. Πράσσων is the practice, while ποιῶν may be the doing once for all. Thus ποιεῖν is to conclude a peace: πράσσειν, to negotiate a peace. So Demosthenes: “He will do (πράξει) these things, and will accomplish them (ποιήσει).” In the New Testament a tendency is observable to use ποιεῖν in a good sense, and πράσσωιν in an evil sense. Compare the kindred word πρᾶξις, deed or work, which occurs six times, and in four out of the six of evil doing (Mat 16:27; Luk 23:51; Act 19:18; Rom 8:13; Rom 12:14; Col 3:9). With this passage compare especially Joh 5:29, where the two verbs are used with the two nouns as here. Also, Rom 7:15, Rom 7:19. Bengel says: “Evil is restless: it is busier than truth.” In Rom 1:32; Rom 2:3, both verbs are used of doing evil, but still with a distinction in that πράσσω is the more comprehensive term, designating the pursuit of evil as the aim of the activity.