From John Paul the Great's Letter to Priests, Holy Thursday, 2004:
We were born from the Eucharist. If we can truly say that the whole Church lives from the Eucharist (“Ecclesia de Eucharistia vivit”), as I reaffirmed in my recent Encyclical, we can say the same thing about the ministerial priesthood: it is born, lives, works and bears fruit “de Eucharistia”(cf. Council of Trent, Sess. XXII, canon 2: DS 1752). “There can be no Eucharist without the priesthood, just as there can be no priesthood without the Eucharist."