11 Believe me that I am in the Father, and the Father in me: or else believe me for the very works' sake.

[I am in the Father, and the Father in me] We are one.

[Believe me for the very works' sake] We are not only one in nature, we are one in operation. Such miracles as I have wrought could only be performed by unlimited power.

12 Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father.

And greater works than these] The miracles which I have wrought could not have been wrought by less than the omnipotence of God; but that omnipotence can work greater. And those who believe on my name shall, through my almighty power, be enabled to work greater miracles than those which I have ordinarily wrought. An imposter may seduce the people by false miracles; but he cannot make his power pass to those who were seduced by him; but I will give you this proof of the divinity of my mission and the truth of my doctrine.
Some examples of "works" and "greater works" are:

1. The very shadow of Peter healed the diseased, Acts 5:15,
2. Diseases were cured and demons cast out by applying to persons handkerchiefs and aprons which had before touched the body of Paul, Acts 19:12,
3. By the word of Peter, Annanias and Sapphira were struck dead, Acts 5:5-10,
4. Elymas the sorcerer was struck blind by the word of Paul, Acts 13:11,
5. Christ preached only in Judea and in the language only of that country, but the apostles preached, at least on the occasion of Pentecost, to people from all the nations of the then known world in their own language, Acts 2:1-12.

[Because I go unto my Father.] Where I shall be intercessor for you.

13 And whatsoever ye shall ask in my name, that will I do, that the Father may be glorified in the Son.
14 If ye shall ask any thing in my name, I will do it.

[Whatsoever ye shall ask in my name] The purpose for granting these requests is that the Father may be glorified in the Son.

15 If ye love me, keep my commandments.

Do not be distraught at the thought of my being separated from you; the most solid proof you can give of your attachment to and affection for me is to keep my commandments. This I shall receive as a greater proof than your tears.

16 And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;

[I will pray the Father] After having made atonement for the sin of the world, I will become the mediator between God and man; and through my mediation and intercession shall all the blessings of grace and glory be acquired.

[Another comfortor] the Greek word paraclatos signifies not only a comfortor, but also an advocate, a defender of a cause, a counsellor, patron, mediator. In 1 John 2:1, the same word, referring to Christ, is translated "advocate." Christ is thus called, because he is represented as transacting the concerns of our souls with God; and for this cause he tells us he goes unto the Father. The Holy Spirit is thus called, because he transacts the cause of God and Christ with us; explains to us the nature and importance of the great atonement, shows the necessity of it, counsels us to receive it, instructs us how to lay hold on it, vindicates our claim to it and makes intercession for us with unutterable groanings, John 16:12-15, Romans 8:26-27. As Christ acted with his disciples while he sojourned with them, so the Holy Ghost acts with us who believe on his name.

[For ever] As the death and atonement of Christ is effective until the conclusion of the world, so the work of the Holy Spirit will be continued in the hearts of believers until the end of time.

17 Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.

[The Spirit of truth] The Spirit of God, or Holy Ghost, whose essential office is to glorify Christ, urging the unsaved to believe in Him and to teach, guide and empower Christians to serve Christ their Savior.

[The world cannot receive] By the world, John means those who are not believers in Christ, those who are influenced only by the desire of the flesh, the desire of the eye and the pride of life, 1 John 2:16. These cannot receive the Spirit of the truth because they see him not, have no spiritual discernment, are consumed by the concerns of this present life, and permit no influence but what may be identified by their senses.

[Shall be in you] God the Father, Christ the Son and the Holy Spirit are all one. Speaking to his believing disciples and to all future believers; God, in the form of Jesus Christ will soon be leaving you, but God, in the form of the Holy Spirit will be with you, in fact within you. The new birth spoken of in John 3 is the event caused by the Holy Spirit coming to live within the believer. John 3:6-7, 2 Corinthians 5:17.

18 I will not leave you comfortless: I will come to you.

[I will not leave you comfortless] Literally, orphans. Such children are destitute of comfort, direction and support, and are prey to misery and disease, to sin and to death. Christ called his disciples children, beloved children, and, now that he is about to be removed from them by death, assures them that they shall not be left fatherless, for in a little time he will come again, (rise from the dead), and after his ascension, they will be made partakers of that Spirit which will be their comforter, advocate, teacher, and guide forever.

19 Yet a little while, and the world seeth me no more; but ye see me: because I live, ye shall live also.

[The world seeth me no more] The world which rejected him and would soon crucify him, desires to put him out of it's mind.

[Because I live] As surely as I will rise from the dead, so shall you. My resurrection will be proof and pledge of yours.