αλλον (form of αλλος, meaning "another", 14:16) By using the word "another" Jesus here identifies himself with the work of the Spirit. The Spirit's activity will be the same as Jesus.
παρακλετος (literally 'paraklete', meaning "counselor", 14:16) I've done a longer posts on this word, you can read about this here: http://lectionarygreek.blogspot.com/2013/05/john-1612-15-holy-trinity-sunday-year-c.html Key nuggets
- Paraklete is often translated "advocate"; this is very "cold" translation of this term. The idea is for more intimate in John's Gospel
- When advocacy is done by the Spirit, it is not protecting us from God's judgment, but rather giving us words of witness before the world.
What is at stake here? Too often we have a bad Trinitarian formulation in that God the Father is mad, God the son is bloody and God the Spirit is somehow arguing to God the Father that God the Father's judgment is all wrong. Jesus is saying that God's Spirit will continue the work Jesus has done, to bring humanity back to God.
αληθεια (it adds an ς in the genitive case, means 'truth', 14.17) First, I consider it ironic that the comforter is one who brings truth. Typically truth and comfort do not go hand in hand! Second, it is worth noting that Jesus just proclaimed himself the way, truth and life. Now the Spirit is the vessel of truth. Again, connecting the word of the Spirit and Jesus!
υμιν (you plural in dative form, 14.17 and 14.20) Throughout this section, the you is always in the plural: "All y'all will live." "I am with all y'all." This is especially worth noting when Jesus says "I am in you." Typically we hear this in an inner-personal way -- Jesus is in my heart. Yet this construction: "εν υμιν" (20) should more be translated "among you." The evidence of Jesus is not found within our own heart, but within the whole community.