Who is this King of Glory?  With the image of Jesus on the cross, recall Isaiah 53:3:

He was despised and rejected by men;
    a man of sorrows, and acquainted with grief;
and as one from whom men hide their faces
    he was despised, and we esteemed him not.

Fr. Timothy Lowe looks to the Gospel of Matthew as the climax to the biblical story in the people's search for a leader.  The Son of Man is presented as an anti-king, securing no power in an army, palace, or wealth.  As one who submits to the will of His Father, the Son of Man will come in glory to judge on that very basis, separating those who serve the will of the Father from those who do not.  This is our hope, even as we are made to tremble.