"You are already clean because of the word I have spoken to you." John 15:3 (NIV)
The English word “clean” translated from the Greek word καθαροί, transliterated into English as katharoi, appears in John’s gospel only once in the incident of the foot washing (John 13:1ff). The range of meaning of the root word, καθαρός is clean, clear, pure. It means free from impure admixture, without blemish, spotless and is used (1) physically (Mt 23:26; 27:59); (2) figuratively, (Jn 13:10) where the Lord teaches that one who has been entirely cleansed need no radical renewal, but only to be cleansed from every sin into which he may fall (Jn 15:3; Heb 10:22); (3) in a Levitical sense (Rom 14:20; Titus 1:15), pure; and, (4) ethically, with the significance free from corrupt desire, from guilt (Mt 5:8; Jn 13:10-11; 1 Ti 1:5; 3:9). καθαρός refers to the Christian’s freedom from the defilements of the flesh and the world (Strong’s 2513).
“A word is a symbol that refers to a concept or entity. The question that we pursue when examining the meaning of a word in each context is, “What sense is present here?” or “What concept is the word intending to invoke here?” (Thornhill, 181). Jesus in John 15 focuses on the Father as the Vine Keeper, and in keeping with the vine metaphor, he adds the phrase, “You are already clean because of the word which I have spoken to you” (Jn 15:3), as a play on words. Jesus makes it clear that cleanliness is “because of the word” (John 15:3). Jesus is encouraging the disciples that the disciples are “already clean” on account of Jesus’ word (i.e., his whole message) that they should continue to progress spiritually as they “remain in the word” (John 15:4) (Morris, 595).
Morris, Leon. The Gospel of John. The New International Commentary on the New Testament. Grand Rapids: Wm. B. Eerdmans Publishing Co., 1995.
Strong, James. The New Strong's Expanded Exhaustive Concordance of the Bible. Red Letter Edition. Thomas Nelson Publishers, 2010.
Thornhill, Chadwick, A. Greek for Everyone: Introductory Greek for Bible Study and Application, Grand Rapids, MI: Baker Books, 2016.