It is by the presence of the Spirit within us that our relationship to Jesus is made real,
"And I will pray the Father, and He will give you another Helper, that He may abide with you forever””the Spirit of truth, whom the world cannot receive, because it neither sees Him nor knows Him; but you know Him, for He dwells with you and will be in you. I will not leave you orphans; I will come to you...At that day you will know that I am in My Father, and you in Me, and I in you...If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our home with him." (John 14:16-24)
Our covenant relationship to God hinges on the Holy Spirit being given to dwell within them. Jesus said that the day of the coming of the Spirit would be the day of their coming to know union. "In that day" i.e. the day of the Spirit coming, they would know "I am in My Father and you in Me and I in you" and again, "We will come to him and make Our home with him." There is not a more intense phrase to describe our union than "you are in Me and I in you." Your body, your mind and emotions are the home of deity through the presence of the Spirit. Stop and let these words sink in, hold your skin and know the Spirit dwells in every cell of your body.
Malcolm Smith - The Lost Secret Of The New Covenant