26 But when the Comforter is come, whom I will send unto you from the Father, [even] the Spirit of truth, which proceedeth from the Father, he shall bear witness of me:
This is a witness of transformation being adopted into the kingdom of the Son, from Darkness to Light. being delivered from darkness by God into the Kingdom of his Son (Colossians 1:13).
7 Nevertheless I tell you the truth: It is expedient for you that I go away; for if I go not away, the Comforter will not come unto you; but if I go, I will send him unto you.
A promise to his disciples to not give up believing and having faith, as Jesus would sent the Comforter to them. The Comforter is a witness, of being born-again, and being made right with God through Jesus. (Romans 5:1-6)
Not really sure, what is missing here? As I did state I do not see 3 people in one God, but do see that the Father, and the Word, and the Holy Spirit are all one.
One what, is the question? One in purpose and essence, they are the one(s) that make up the realities of Heaven.
Firstly God - being Yahweh.
Second God's Word - which became Jesus
Third the Holy Spirit of God - which was the comforter you mentioned earlier.
I base this off of - 1 John 5:7.
Hope this helps answer your question.
Thank you for your question,
@Marymog .