"Every branch in Me that does not bear fruit He takes away; and every branch that bears fruit He prunes, that it may bear more fruit." (John 15:2)
John 15:2 sets forth a major emphasis on the relationship of the believer to Christ. Jesus' exhortation throughout this portion of His discourse is that, as Christians, as His disciples, we are to be fruitful. That is, we are to be productive.
This theme is declared so often in the pages of the New Testament, you would think it would be almost a cliché among Christians, but that is not the case. I frequently encounter the idea in the Christian world, and particularly in academic circles, that if you are a Christian, you do not really have to do very much. The idea is that since we are justified by grace through faith alone, works are utterly inconsequential, so we can kick back, take our ease in Zion, rest on the grace of God, and be utterly worthless for His kingdom. It seems that our proper emphasis on the monergistic saving work of God causes us to give no heed to the Bible's calls to good works. We must see that while we are justified by faith apart from works, we are justified by faith unto works.
What is the fruit Jesus is concerned to see in our lives? There has been much debate about that. Some believe that the only fruit Jesus is concerned about is people coming to saving faith in Him. In other words, "bearing fruit" means leading people to Christ. Others argue that the fruit is obedience to the law of God. Certainly both of these aspects are important, and both are involved in bearing fruit, but the central emphasis on fruit in the New Testament has to do with the fruit of the Holy Spirit. This is the fruit of a changed life, a changed character, a character that is strengthened and nurtured by the source of holiness, Christ Himself.
We must not neglect the warning Jesus gives in this passage: "Every branch in Me that does not bear fruit He takes away; and every branch that bears fruit He prunes, that it may bear more fruit" (v. 2). Frankly, I don't like the translation here. This translation is an attempt to render into English something that simply cannot be communicated in the exact way it comes across in the Greek. In the Greek, there is a play on words, and that's probably the most difficult thing to translate from one language to another. Jesus said that those who do not bear fruit receive from God ario, which means "to be cut off," and everyone who bears fruit receives kathario, which is translated here as "to prune." There is ario and kathario, two words that sound alike. Kathario is the word from which we get the term catharsis, which means "a cleansing." So Jesus said, "Those who are in Me and do not bear fruit are cut off; those who do bear fruit are cleansed, purified, nurtured, and pruned, so that they may become even more productive."
This excerpt is taken from R.C. Sproul's commentary on John.