The nature of the Trinity - God the Father, God the Son and the Holy Spirit - is just something that we will never be able to understand this side of eternity. But it doesn't mean we can't catch glimpses, or marvel at the wonder of God. The Bible does pas.
Jesus called the Spirit the Comforter, and sometimes the Holy Ghost. It is the presence of the Spirit that sanctifies and convicts Christians after they are saved. It is the Spirit who works in the lives of unbelievers as well, testifying to the truth of .