Homily II on the Dormition, 2 — as quoted by Pitre (p 63); translation: Brian E. Daley, On the Dormition of Mary (St Vladimir's Seminary Press, 1998)
Today the holy, incomparable virgin enters the heavenly sanctuary that lies above the universe…Today the holy, living ark of the living God, the one who carried her own maker within herself, comes to her rest in the temple of the Lord not made by hands. David—her ancestor and God's—leaps for joy; the angels join in the dance.
No freely usable English translation of this passage is online, so the note keeps Pitre's quotation and links to the full text. Translation: Brian E. Daley, On the Dormition of Mary (St Vladimir's Seminary Press, 1998), as quoted by Pitre.
Why Pitre cites it
'Today the holy, living ark of the living God, the one who carried her own maker within herself, comes to her rest in the temple of the Lord not made by hands. David… leaps for joy.' The other Father Pius XII cited for the Assumption.