What does John 16:15 mean?
As Jesus prepares for His impending arrest and execution (John 18:1–3; 19:18), He reassures the disciples by predicting the coming of the Holy Spirit. Much of what Jesus has said was not understood by His closest followers (John 2:22; 16:17). Only after His resurrection, and with the empowerment of the Spirit, will they be able to fully grasp all that is happening (John 16:12–13).In this statement, Jesus once again asserts that He is divine. Likewise, He refers to the Holy Spirit in tying together all three members of the Trinity (John 16:14). John began his gospel explaining that Jesus' presence on earth gloriously presented the truth of God (John 1:14).
The guidance of the Holy Spirit will always lead a person towards or "into" truth. That does not mean every claim of inspiration is true—born-again Christians can be sincerely wrong (Galatians 2:11–14). Other spiritual voices can lead us astray (Galatians 1:8; 2 Corinthians 11:4). Discipleship and the written Word are crucial in the process of following God (Matthew 28:19; Acts 8:31; 1 Corinthians 4:6). However, the voice of the Spirit provides insight which is simply unavailable to those who are not believers (1 Corinthians 2:14).