The most important person on the face of the earth is the Holy Spirit of God.
He, despite being part of the Divine Trinity, is the least recognized person and sometimes, in the wrong way, considered the third person or third place of the Trinity, as if he were less God than the father or the son.
The Holy Spirit was sent to Earth by God the Father after Jesus finished his mission on Earth and ascended glorified to heaven. The spirit is now within each son of God and is a constant and faithful companion. If you allow it and pay attention to it, he will guide you constantly to all truth, he will reveal the written word of God the Father and also bring to your mind all that Jesus declared while he was on Earth. Be sure to receive the gift of God the Father and be one with his spirit.