In the book of Revelation, we find a powerful image of the Lord who knocks on the door of our hearts, and waits to be welcomed inside: “Behold, I stand at the door and knock. If anyone hears my voice and opens the door, I will enter his house and dine with him, and he with me” (Revelation 3:20).
Jesus knocks at the door of our hearts and eagerly desires to dine with us at the sacrificial meal we call the Eucharist. He wishes to find us ready to receive him, to sit down and eat with him, in the upper rooms of our lives.
—from Monsignor Peter J. Vaghi's book Meeting God in the Upper Room: Three Moments to Change Your Life