“For through him, we both have access to the Father by one Spirit” (Eph. 2.18).

We have access to the Father as sons and daughters in union with the Son. The Father is relational. He always relates to his unique Son in joyful love. And he wants to relate to us in the same way. For Jesus said his Father loves us just as he loves his unique Son.
 
THROUGH HIM (Jesus) we have access to the Father. On the Day of Atonement, the high priest entered the most holy place as the representative of the people. Jesus, our high priest, has entered the Most Holy Place as our representative.  As he presents himself before the Father, he presents us to the Father. He presents us in himself and with himself.  He does so having offered himself as the once for all sacrifice for our sins. And so, through Jesus, access into the Father’s presence is opened wide for all of us.  He enters for us and we enter with him. We don’t move into the Father’s presence in our own names and through our own merit, but always through Jesus our High Priest.

We have free and open access to enter with confidence through him. And we do so BY ONE SPIRIT. The exalted Jesus received from his Father the gift of the Spirit for us.
And he pours this Spirit on us and in us freely. Now we can draw near in the Spirit so that we do not know God from afar. In the communion of the Spirit, we may know God closely as he is in himself. He is a communion of loving relationship within himself and we are allowed to share in the fellowship as the Spirit brings us near.