In the Assumption of Mary into heaven we see what grace is meant to lead us to. Grace is a participation in the life of God. A participation where we begin to live being united to Him.
I pray not only for them, but also for those who will believe in me through their word, so that they may all be one, as you, Father, are in me and I in you, that they also may be in us, that the world may believe that you sent me. John 17:20-21
In the Assumption we see her being taken up by the God she is united with. From the readings for the Vigil of the Assumption, Mary’s unique role in salvation history is highlighted.