Wilbur Pickering has some great commentary on John 15:1-6:
1 “I am the vine, the true one, and my Father is the vinedresser.
2 Any branch in me which does not produce fruit He lifts up, and every one producing fruit
He prunes, so that it may produce more fruit.
3 You are already clean because of the word that I have spoken to you.
4 Abide in me and I in you. Just as a branch is incapable of producing fruit by itself, except
it remains in the vine, so neither can you unless you abide in me.
5 “I am the vine, and you are the branches. The one who abides in me and I in him, he is
the one who produces much fruit, because apart from me you are incapable of doing
6 If anyone does not abide in me he is thrown out, like a branch, and dries up; well they
gather such and throw them into the fire, and he is burned up. (WPNT)
“From the way this is stated I conclude that although this ‘abiding’ is a two-way street, it actually depends on us. That is, as we abide in Him He will abide in us— He won’t stop first; only if we stop abiding in Him will He stop abiding in us.
We seem to have a hard time getting this through our heads, but our Lord is very clear— all our activism is fruitless. If we wish to produce fruit for Christ’s Kingdom we MUST abide in Him.
That’s what the Text says, ‘he’ is burned. The direct object of ‘gather’ and ‘throw’ is plural (referring to what normally happens to dead branches), but the subject of ‘be burned’ is singular. The ‘he’ must refer back to the beginning of the verse, to the one who does not abide in Christ. Few figures of speech fit in every detail. Of course an actual branch cannot just decide to jump out of its vine or tree; an outside force must cut or break it off. But we have volition— verbs like ‘abide’ or ‘remain’ clearly imply that the choice is up to us; we can indeed decide to leave our Vine, we can stop believing. Notice again the sequence of events, “if anyone does not abide in me he is thrown out”— a branch that is ‘abiding’ is not thrown ; only if you choose to leave will you be thrown. I am a theologian (ThM) and am well aware that people tend to buy into a theological system, or doctrinal package, and they then impose that system on the Bible— if some passage doesn’t fit they do whatever damage may be necessary to that passage to make it ‘fit’. But I am also a linguist (PhD), and I know that human language is governed by rules— to disobey those rules is a form of lying, and God cannot lie (Titus 1: 2), so if in interpreting the Bible you disobey those rules you make a liar out of God, which isn’t very smart! In this passage the Lord Jesus Christ gives instruction that is perfectly plain. If the Word of Christ says one thing and your doctrinal package says another, then you had better stop and think. Which holds more authority for you, which are you going to follow, the Word of Christ or your doctrinal package? If you choose the latter, you are an idolater— to place your church’s doctrine above the Word of God is a form of idolatry. Idolatry isn’t nice.”
Pickering ThM. PhD., Dr. Wilbur (2013-11-15). THE SOVEREIGN CREATOR HAS SPOKEN — New Testament Translation with Commentary (Kindle Locations 20853-20863). – Kindle Edition –