On the First Office of the Mass
Now, the Mass is divided into seven offices. In the first, Christ’s legation is performed, which we know was prefigured by Moses, who is chosen the God of the gentiles, pope of priests, and king of peoples. For by God he is appointed the God of Pharaoh, the prophet of Aaron the priest, and the leader of the people. He performs the legation of God in Egypt, is received by the elders and the people, gathers the dispersed people, subdues Egypt through signs, and freeing the oppressed from tyranny and harsh servitude he leads them from Egypt and brings them into the land of the promise.
Just so Christ, the God of gods, priest of priests, and king of kings performs the legation of the Father in the world: the shepherd is received by the angels and shepherds who are the type of the Church. He who gathers into one faith the sons of God who had been dispersed subdues the world with various signs. Freeing from Hell those oppressed by the devil, he leads them into the homeland of paradise.
All of this is represented to us by the procession of the bishop, who bears the figure of Christ.
De primo officio.
Missa autem in septem officia distinguitur. In primo quorum Christi legatio agitur, quam Moyses praefigurasse cognoscitur, qui Deus gentilium, papa sacerdotum, rex populorum legitur. A Deo namque Deus Pharaonis, propheta Aaron sacerdotis, dux populi constituitur. Hic legatione Dei in Aegyptum fungitur, a senioribus et populo suscipitur, populum dispersum congregat, Aegyptum signis perdomat, oppressos a tyranno de dura servitute liberans, de Aegypto educit, in terram promissionis inducit, Sic Christus Deus deorum, sacerdos sacerdotum, rex regum, legatione Patris in mundum fungitur, ab angelis et pastoribus pastor, Ecclesiae typum excipitur gerentibus. Qui filios Dei, qui erant dispersi, in unam fidem congregat, mundum variis signis subiugat. Oppressos a diabolo liberans de inferno educit, in patriam paradisi inducit. Hoc totum repraesentat nobis processio episcopi, qui gerit figuram Christi.