The Holy Spirit is the agent who grants a believer communion with the Father, the Son, and the Holy Spirit.  This is a communion for which we were originally created and for which the Father elected the Son to redeem us.  Salvation is not merely from the horrors of a real place called hell nor even merely also to the joys of a place called Heaven.  Salvation is gained supremely through acceptance of the invitation to enter into an eternal relation with the Triune God!

(H)uman participation in the Trinity is derivative – by grace, not by essence.  And in the spite of our created status, we are nevertheless granted a place with God, in relationship with all three subjects of the Trinity.  For love He created us – Father, Son, and Holy Spirit.  By grace He redeems us – Son, Father, and Holy Spirit.  For communion He communes with us – Holy Spirit, Son, and Father.  We are intended for life “with” and “after” Him.

Yarnell, Malcolm B.  (2016).  God the Trinity.  Nashville:  B&H Academic.