Christians believe that the Holy Spirit -- what John 16:13 calls the Spirit of truth -- descended upon the Christians on the day of Pentecost. On that wonderful day the apostles performed miracles and Peter preached his first sermon. About three thousand people became Christians on that day. You can read about these events in the second chapter of Acts.
The New Testament speaks of "the church" and "the gospel." Jesus envisioned one church led by the Holy Spirit and in possession of "all truth." In today's world, however, there are thousands of churches (denominations), each of which asserts that it teaches the truth. The likelihood that any of these churches is in possession of "all truth" is very small. The churches disagree on fundamental questions even though they all use the same Bible. Given this state of affairs, I conclude that the "Spirit of truth" spoken of in John 16:13 does not exist or does not know how to communicate a clear message. Nor does the Bible communicate a clear message. I will provide one example. Jesus taught the importance of God's commandments. Salvation comes from obedience to the commandments. See, for example, Matthew 19:16-17 and Matthew 5:17-20. But Paul taught that salvation is a gift one receives through faith in Jesus, not through obedience to the commandments. "A man is justified by faith apart from observing the law." Romans 3:28.
