A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
joh 15:1DISCOURSE AT THE SUPPER TABLE CONTINUED. (John 15:1-27)
The spiritual oneness of Christ and His people, and His relation to them as the Source of all their spiritual life and fruitfulness, are here beautifully set forth by a figure familiar to Jewish ears (Isa 5:1, &c.).
I am the true vine--of whom the vine of nature is but a shadow.
my Father is the husbandman--the great Proprietor of the vineyard, the Lord of the spiritual kingdom. (It is surely unnecessary to point out the claim to supreme divinity involved in this).
joh 15:2Every branch in me that beareth not fruit . . . every branch that beareth fruit--As in a fruit tree, some branches may be fruitful, others quite barren, according as there is a vital connection between the branch and the stock, or no vital connection; so the disciples of Christ may be spiritually fruitful or the reverse, according as they are vitally and spiritually connected with Christ, or but externally and mechanically attached to Him. The fruitless He "taketh away" (see on Joh 15:6); the fruitful He "purgeth" (cleanseth, pruneth)--stripping it, as the husbandman does, of what is rank (Mar 4:19), "that it may bring forth more fruit"; a process often painful, but no less needful and beneficial than in the natural husbandry.
joh 15:3Now--rather, "Already."
ye are clean through--by reason of.
the word I have spoken to you--already in a purified, fruitful condition, in consequence of the long action upon them of that searching "word" which was "as a refiner's fire" (Mal 3:2-3).
joh 15:4Abide in me, and I in you; as the branch cannot bear fruit of itself, except it abide in the vine, &c.--As all spiritual fruitfulness had been ascribed to the mutual inhabitation, and living, active interpenetration (so to speak) of Christ and His disciples, so here the keeping up of this vital connection is made essential to continued fruitfulness.
joh 15:5without me--apart, or vitally disconnected from Me.
ye can do nothing--spiritually, acceptably.
joh 15:6If a man abide not in me, he is cast forth as a branch . . . withered . . . cast into the fire . . . burned--The one proper use of the vine is to bear fruit; failing this, it is good for one other thing--fuel. (See Eze 15:1-5). How awfully striking the figure, in this view of it!
joh 15:7If ye abide in me, and my words . . . in you--Mark the change from the inhabitation of Himself to that of His words, paving the way for the subsequent exhortations (Joh 15:9-10).
ask what ye will, and it shall be done unto you--because this indwelling of His words in them would secure the harmony of their askings with the divine will.
joh 15:8glorified that ye bear much fruit--not only from His delight in it for its own sake, but as from "the juices of the Living Vine."
so shall ye be my disciples--evidence your discipleship.
joh 15:9continue ye in my love--not, "Continue to love Me," but, "Continue in the possession and enjoyment of My love to you"; as is evident from the next words.
joh 15:10If ye keep my commandments, ye shall abide in my love--the obedient spirit of true discipleship cherishing and attracting the continuance and increase of Christ's love; and this, He adds, was the secret even of His own abiding in His Father's love!
joh 15:12That ye love one another, &c.--(See on Joh 13:34-35).
joh 15:13Greater love hath no man than this, that a man lay down his life for his friends--The emphasis lies not on "friends," but on "laying down his life" for them; that is, "One can show no greater regard for those dear to him than to give his life for them, and this is the love ye shall find in Me."
joh 15:14Ye are my friends, if ye do whatsoever I command you--hold yourselves in absolute subjection to Me.
joh 15:15Henceforth I call you not servants--that is, in the sense explained in the next words; for servants He still calls them (Joh 15:20), and they delight to call themselves so, in the sense of being "under law to Christ" (Co1 9:20).
the servant knoweth not what his lord doeth--knows nothing of his master's plans and reasons, but simply receives and executes his orders.
but . . . friends, for all things that I have heard of my Father I have made known unto you--admitted you to free, unrestrained fellowship, keeping back nothing from you which I have received to communicate. (Compare Gen 18:17; Psa 25:14; Isa 50:4).
joh 15:16Ye have not chosen me, but I . . . you--a wholesale memento after the lofty things He had just said about their mutual indwelling, and the unreservedness of the friendship they had been admitted to.
you, that ye should go and bring forth fruit--that is, give yourselves to it.
and that your fruit should remain--showing itself to be an imperishable and ever growing principle. (Compare Pro 4:18; Jo2 1:8).
that whatsoever ye shall ask, &c.--(See on Joh 15:7).
joh 15:17The substance of these important verses has occurred more than once before. (See on Mat 10:34-36; Luk 12:49-53, &c.).
joh 15:22(See on Joh 9:39-41).
If I had not come and spoken unto them, they had not had sin--comparatively none; all other sins being light compared with the rejection of the Son of God.
now they have no cloak for their sin--rather, "pretext."
joh 15:24If I had not done . . . the works which none other . . . did--(See on Joh 12:37).
joh 15:25that the word might be fulfilled . . . They hated me without a cause--quoted from the Messianic Psa 69:4, applied also in the same sense in Joh 2:17; Act 1:20; Rom 11:9-10; Rom 15:3.
joh 15:26(See on Joh 14:15; Joh 14:17).
joh 15:27ye also shall bear witness--rather, "are witnesses"; with reference indeed to their future witness-bearing, but putting the emphasis upon their present ample opportunities for acquiring their qualifications for that great office, inasmuch as they had been "with Him from the beginning." (See on Luk 1:2).