Bring forth therefore (vide supra) fruits; fruit (Revised Version). The plural is due to a false reading taken from the parallel passage of Luke—it regards the various graces of a good life as so many different fruits (Matthew 21:43); the singular, as one product from one source (Galatians 5:22).
The term used here ( ποιεῖν καρπόν), and frequently, lays more stress on the effort involved than διδόναι καρπόν, simple "yielding" (Matthew 8:8), or φέρειν, "bearing" in the course of nature. The preacher requires a repentance which produces results.
Meet for (of. Acts 26:20). Though strictly meaning "suitable to", the phrase might today be understood as "suitable to produce." John really means that true repentance has fruit which belongs to its proper nature, and which is alone "worthy of" it (Revised Version).
Repentance ( τῆς μετανοίας). The article is either generic (Authorized Version and Revised Version; cf. Acts 11:18 and probably Acts 26:20); or equivalent to "your". If the latter, the following sentence shows that it is still said in good faith.
(For repentance, of. verse 1, note.