Charles Ellicott Commentary John 14:17

"[even] the Spirit of truth: whom the world cannot receive; for it beholdeth him not, neither knoweth him: ye know him; for he abideth with you, and shall be in you." — John 14:17 (ASV)

Even the Spirit of truth.—Compare to John 15:26; John 16:13; 1 John 5:6. He is called the Spirit of Truth because part of His special office is to bring truth home to the hearts of people, to carry it from the material to the moral sphere, to make it something more than a collection of signs seen or heard—a living power in living people.

Whom the world cannot receive.—The Holy Spirit can be received only by those who have the spiritual faculty. It cannot be otherwise. The unbelieving world, caring only for things of the senses, has lost its spiritual perception. It has no eye to see and no heart to know spiritual things, for they are spiritually discerned (Compare to the note on 1 Corinthians 2:14).

But you know him; for he dwells with you, and will be in you.—The better text reads, ... and is in you. The verbs are in the present tense, describing the receptivity of the disciples as opposed to the moral blindness of the world. They had, during our Lord’s work and teaching in their midst, exercised and strengthened their spiritual faculties. They had in part received the Spirit, and by that reception were prepared for the fuller gift. They knew Him. He was in their midst. He was then, and therefore would be in the future, a living power, dwelling in their inmost life.