How Is God inside Us?
When Jesus was sitting at the Seder meal we now call the last supper and after he had instituted the sacrament of the Lord's Table, he talked to the disciples about their life together and about his betrayal and the apostles' relationship with him and with God after his resurrection (John 14). Jesus promised that he would not leave us "orphaned" without a guide or guardian: He would send someone who would stand beside us and comfort us. This new advocate would be known as the Holy Spirit.
The Holy Spirit is a "go-between God." God's Spirit is experienced not as another human the way the apostles had experienced Jesus and not as an entity at a distance from creation as many ancient believers understood the creator God. The Holy Spirit is much like the wireless connection among a laptop, a printer, and a router. She is present in each machine at the same time and is present in the space among all the laptops, printers, and the router as well, the Holy Spirit dwells in us and connects us with our heavenly parent giving us the power to love, and to praise, and to do all we are called on to do.
There is some confusion as to who the Holy Spirit is and how the Spirit exists inside us. In some non-Christian traditions, the Holy Spirit is understood as a fragment of the one God that broke off at creation and draws persons back to the deity for reconnection much like a small magnet would be drawn to another more powerful magnet. That image and story of the Holy Spirit--although picturesque--has no relationship to the biblical account.
Many persons without religious training imagine the Holy Spirit to be the individual's conscience; however, we understand the conscience to be a socially constructed set of rules and values. The structure of an individual's conscience says more about his parents' rules and the mores of the culture he grew up in than it says about anything divine.
Presbyterians along with most orthodox Christians believe that the Holy Spirit is fully God and fully present inside every Christian. This Spirit dwells in us not to make us feel guilty if we break a social or cultural prohibition, but to give us new insight and power to do what is right. This grace and power to do right is sometimes referred to as "the fruit of the Spirit." The Holy Spirit does struggle within us to help us move beyond cultural norms to challenge the idolatries that ego and culture present, but she is more than merely a voice in our head.
The Holy Spirit has the task of drawing us to heaven but not because we will then achieve our salvation through unity with the greater Spiritual entity. With her inside us we are already beginning to experience salvation because we are already "in the presence of God." Because of the presence of the Spirit, the kingdom of God is not only a future goal; the kingdom is among us now.