The phrase "when the Spirit of truth comes" refers to a promise Jesus made to His disciples about the coming of the Holy Spirit. According to John 16:13, when the Spirit of truth comes, He will guide believers into all truth. The Spirit will not speak on His own authority but will convey what He hears from the Father and the Son. The Spirit will declare things to come, glorify Jesus, and reveal all that belongs to the Father, who gave everything to Jesus. This means the Spirit will lead believers into understanding the fullness of God's truth and guide them in their spiritual lives. This coming of the Spirit of truth was a promise Jesus made before His ascension, referring to the Holy Spirit who would dwell within believers after Jesus' departure, helping them know and understand God, His word, and the truth about the world and themselves.