The following is an excerpt from The MacArthur New Testament Commentary on John 15.
Every branch in Me that does not bear fruit, He takes away; … If anyone does not abide in Me, he is thrown away as a branch and dries up; and they gather them, and cast them into the fire and they are burned. (John 15:2a, 6)
A very different fate awaits the branches that do not bear fruit. Because they are detrimental to the health of the vine, the vinedresser would cut off the dry, lifeless, withered branches. In the Lord’s analogy, the vinedresser (the Father) takes the unregenerate false branches away from their superficial attachment to the vine, and they are thrown away.
The reference here is not, as some imagine, to true Christians losing their salvation, nor are these fruitless but genuine Christians (an impossibility, as we have seen). That these branches bear no fruit marks them as unbelieving, false disciples since, as noted previously, all true Christians bear fruit. Further, Jesus promised that He will not cast out any true disciples: “All that the Father gives Me will come to Me, and the one who comes to Me I will certainly not cast out” (John 6:37).
The phrase in Me in this case cannot have the Pauline connotation of believers’ union with Christ; it merely describes those who outwardly attach themselves to Him (cf. Matt. 13:20–22; Rom. 9:6–8; 11:16–24; 1 John 2:19). Such people will always be present with the true church. The New Testament describes them as tares among the wheat (Matt. 13:25–30); bad fish that are thrown away (Matt. 13:48); goats condemned to eternal punishment (Matt. 25:33, 41); those left standing outside when the head of the house shuts the door (Luke 13:25–27); foolish virgins shut out of the wedding feast (Matt. 25:1–12); useless slaves who bury their master’s talent in the ground (Matt. 25:24–30); apostates who eventually leave the fellowship of believers (1 John 2:19), manifest an evil, unbelieving heart by abandoning the living God (Heb. 3:12), continue to sin willfully after receiving the knowledge of the truth (Heb. 10:26), and fall away from the truth to everlasting destruction (Heb. 10:39). Although they imagine that they are on their way to heaven, they are actually on the broad path leading to hell (Matt. 7:13–14).
Right in their presence was the quintessential example of a false branch—Judas Iscariot. Outwardly, he was indistinguishable from the other eleven apostles—so much so that when Jesus announced earlier that night, “Truly, truly, I say to you, that one of you will betray Me” (John 13:21), the other “disciples began looking at one another, at a loss to know of which one He was speaking” (v. 22). They finally had to ask Him to point out His betrayer (vv. 23–26). But Judas had never been saved. In John 6:70–71 Jesus said to the apostles, “ ‘Did I Myself not choose you, the twelve, and yet one of you is a devil?’ Now He meant Judas the son of Simon Iscariot, for he, one of the twelve, was going to betray Him.”
The ultimate fate that awaits the false branches is to be cast … into the fire and … burned. In Matthew 13:49–50 Jesus warned that “at the end of the age the angels will come forth and take out the wicked from among the righteous, and will throw them into the furnace of fire; in that place there will be weeping and gnashing of teeth” (cf. Matt. 3:10–12; 7:19; 25:41; Mark 9:43–48; Luke 3:17). Their anguished protest, “Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?” (Matt. 7:22) will evoke the chilling reply from the Lord, “I never knew you; depart from Me, you who practice lawlessness” (Matt. 7:23).
The choice that faces every person is clear. To abide in Christ as a genuine disciple will produce righteous behavior and result in eternal joy and blessing. But those whose profession of faith is false, like Judas, will be fruitless and ultimately cast into eternal torment in hell. The Lord’s sobering pronouncement concerning Judas, “Woe to that man by whom the Son of Man is betrayed! It would have been good for that man if he had not been born” (Matt. 26:24), applies to all pseudodisciples. In the words of Peter, If, after they have escaped the defilements of the world by the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and are overcome, the last state has become worse for them than the first. For it would be better for them not to have known the way of righteousness, than having known it, to turn away from the holy commandment handed on to them (2 Peter 2:20–21).