From the Treasury of Daily Prayer:

Ascension Day is the coronation celebration of our Lord as He is proclaimed to be King of the universe. Jesus’ ascension to the Father is His entrance to the greater existence beyond the confines of time and space, being no longer bound by the limitations of His state of humiliation. Jesus now sits at the right hand of God, which Luther correctly taught is everywhere, having again taken up the power and authority that were His since before time. Yet our Lord is present with us who remain bound by time and space. He is with us as true God and true man, exercising His rulership in the Church through the means of grace which He established: His Word and His Sacraments. We mortals in those means of grace can grasp the King of the universe and receive a foretaste of the feast to come.