John 14:16-28 below tells us five times who the Comforter is, but the moment Christ says “another Comforter,” most become blind to the fact He is referring to Himself despite His clear words that follow.
1. John 14:17 “Even the Spirit of truth [Jesus is the truth and by His Spirit He is the Spirit of truth]; whom the world cannot receive, because it seeth him not, neither knows him: but you know him; for he dwelleth with you, and shall be in you.”
2. John 14:18 “I [Jesus] will not leave you comfortless: I will come to you.”
3. John 14:22 “Judas saith unto him, not Iscariot, Lord, how is it that you [Jesus] will manifest thyself unto us [as the Comforter], and not unto the world?”
4. John 14:23 “If a man love me, he will keep my words: and my Father will love him, and we [Jesus and His Father] will come unto him, and make our abode with him.”
5. John 14:28 “You heard me say, I [Jesus] am going away and I am coming back to you [as the Comforter].”
The Greek word for another is “allos,” which means another of the exact same kind and hence means another as the same kind as Christ. Jesus was present with His disciples in physical form but after the cross He comes back in another form, that is, by His Spirit. Hence the “another” is His Spirit.
Because Christ's Spirit can function independently of Himself, it is like His Spirit is “another.” And because it is His Spirit, it is “another” of the same kind.
If the Comforter was a different person then John would have used the word “heteros” meaning another of a different kind.
Compare “heteros” with “allos”
HELPS Word-studies © 1987, 2011 by Helps Ministries, Inc.
G2087 héteros – another (of a different kind). 2087 /héteros (“another but distinct in kind”) stands in contrast to 243 /állos (“another of the same kind”). 2087 /héteros (“another of a different quality”) emphasizes it is qualitatively different from its counterpart (comparison). [2087 (héteros) sometimes refers to “another” of a different class group or type (as in Plato; Oxy. papyri).]
G243 állos (a primitive word) – another of the same kind; another of a similar type.