Apparently a quote from one of St. Thomas Aquinas' eucharistic hymns. Read it in Aidan Nichols's _The Thought of Benedict XVI_, which is a *superb* book.
The above quote locks in with another quote from one of my patron saints, Ignatius of Loyola:
"There are very few people who realise what God would make of them if they abandoned themselves into his hands, and let themselves be formed by his grace. A thick and shapeless tree-trunk would never believe that it could become a statue, admired as a miracle of sculpture, and would never submit itself to the chisel of the sculptor, who sees by its genius, what he can make of it. Many people who we see now scarcely live as Christians, do not understand that they could become saints, if they would let themselves be formed by the grace of God, and if they did not ruin his plans by resisting the work he wants to do."
(Bartoli, D., Histoire de Saint Ignace et de l'origine de la Compagnie de Jésus, 3rd ed., 2 v. [Brussels, 1852]. Translation of the original Italian of 1650. 2:255)
Cogs turning, clicking, time slipping, dripping, heart beating, panting... Tired, but hopeful, and "peaced"...