What does John 16:13 mean?
Here, again, Jesus refers to the Helper, the Holy Spirit, as the "Spirit of truth" (John 14:16; 15:26). Many aspects of Christ's earthly ministry were misunderstood prior to His resurrection (John 2:22). The work of the Holy Spirit, especially in the lives of the apostles, was to clarify those events (1 Corinthians 2:10). In the lives of all Christian believers, the Holy Spirit provides insight that can't be expected of those without His influence (1 Corinthians 2:14).However, this influence of the Spirit does not impart instant or automatic wisdom. Christ does not say that the Spirit will immediately place the minds of believers into a state of spiritual perfection. Nor does it say the Spirit will totally replace a person's thoughts or opinions. Rather, the Spirit "will speak," "guides," and "declares." That influence can be resisted or even ignored: saved believers, even men like the apostles, can be wrong about spiritual matters (Galatians 2:11–14). Discipleship from other Christians (Matthew 28:19) and the use of the written Word (1 Corinthians 4:6) are crucial in all doctrinal discussions (Acts 8:31).
Jesus' comments here also speak to the mutual relationship between God the Father, God the Son, and God the Holy Spirit.