The Spirit of Truth

Jesus revealed and spoke about the Spirit of truth three times:

“And I will pray the Father, and He will give you another Helper, that He may abide with you forever – the Spirit of truth, whom the world cannot receive, because it neither sees Him nor knows Him; but you know Him, for He dwells with you and will be in you” (John 14:16-17).

“But when the Helper comes, whom I shall send to you from the Father, the Spirit of truth who proceeds from the Father, He will testify of Me. And you also will bear witness, because you have been with Me from the beginning” (John 15:26-27).

“However, when He, the Spirit of truth, has come, He will guide you into all truth; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come” (John 16:13).

Bonus:

“He will glorify Me, for He will take of what is Mine and declare it to you. All things that the Father has are Mine. Therefore I said that He will take of Mine and declare it to you.
A little while, and you will not see Me; and again a little while, and you will see Me, because I go to the Father” (John 16:14-16).