8 “Arise, O Lord, into Your resting place”. He says unto the Lord sleeping, “Arise.” You know already who slept, and who rose again....“You, and the ark of Your sanctification:” that is, Arise, that the ark of Your sanctification, which You have sanctified, may arise also. He is our Head; His ark is His Church: He arose first, the Church will arise also. The body would not dare to promise itself resurrection, save the Head arose first. The Body of Christ, that was born of Mary, has been understood by some to be the ark of sanctification; so that the words mean, Arise with Your Body, that they who believe not may handle.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)