15:1 I am. This is the seventh and last of the “I am” statements of Christ in John’s gospel, all asserting His deity and complete ability to save and reign. The others are, in order: (1) “the bread of life” (John 6:35); (2) “the light of the world” (John 8:12); (3) “the door” (John 10:9); (4) “the good shepherd” (John 10:11); (5) “the resurrection, and the life” (John 11:25); (6) “the way, the truth, and the life” (John 14:6). As the seven “I am’s” affirm His deity, the seven “signs” (see John 20:30-31) confirm it.
15:1 true vine. Israel had been pictured in the Old Testament as a vine that had become unproductive (e.g., Isaiah 5:1-7; Jeremiah 2:21), but Christ here asserts that He Himself is the “true vine,” whose good fruits last forever.
15:2 he taketh away. The true Christian will bear good fruit; the pseudo-Christian will not bear good, lasting fruit, and will therefore ultimately be cast into the fire and burned (John 15:6), just like the pseudo-wheat in the parable of wheat and tares (Matthew 13:28-30,41-42).
15:2 beareth fruit. Note the threefold categories of Christians: (1) fruit-bearing (John 15:2); (2) more fruit-bearing (John 15:2); (3) much fruit-bearing (John 15:5). These seem to correspond to the three categories of wheat-producing Christians—those producing thirtyfold, sixtyfold and hundredfold returns (Matthew 13:8,23).
15:2 purgeth it. The “purging” or “pruning” obviously refers to bringing whatever pressures on the believer may be needed in order to lead him into a more fruitful Christian life and witness.
15:3 clean through the word. The cleansing power of the Word of God is often stressed in the Bible (e.g., Psalm 119:9; Ephesians 5:26).
15:4 Abide in me. The verb “abide” is the same in the Greek as “continue” or “remain,” and is used no less than twelve times in John 15:4-16. The same word is used in John 8:31 when Jesus said those who “continue in my word” are “my disciples indeed.” See also John 15:7. Thus, abiding in Christ is not some mystical concept but simply adhering strictly to the words of Christ as found in the Scriptures, guarding them as true and authoritative in every respect, and seeking to obey them by God’s help.
15:4 cannot bear fruit. There are various kinds of “fruit” which Christians should produce. There is the nine-fold “fruit of the Spirit” (Galatians 5:22-23), manifest in gracious and consistent Christian character, as well as “the fruits of righteousness” (Philippians 1:11; Hebrews 12:11). Ephesians 5:9 says that “the fruit of the Spirit is in all goodness and righteousness and truth,” and all of this will produce fruit in the form of others won to Christ. For example, Paul expressed to the people in Rome his desire to “have some fruit among you also, even as among other Gentiles” (Romans 1:13).
15:5 abideth in me. Certain outward evidences can be observed when one is truly “continuing” in Christ. “He that saith he abideth in Him ought himself also so to walk, even as He walked” (I John 2:6). “Whosoever abideth in Him sinneth not” (I John 3:6). “If ye abide in me, and my words abide in you, ye shall ask what ye will, and it shall be done unto you” (John 15:7). There would be exceptions, of course, for no one is perfect, but these attributes can and should be generally evident in those who are really in Christ.
15:5 can. Here the word “can” here is the Greek dunamai, indicating “have the power to.”