An excerpt from the third book of the Rationale Divinorum Officiorum of William Durandus of Mende, Englished by T.H. Passmore:
1. Lastly, over all the Vestments the Priest putteth on the Chasuble, which is being interpreted a 'little cottage'. It is called by the Greeks the planet, from plane, a wandering, for that its border wandereth wide as it is raised over the arms, signifying charity, without which the Priest is as a SOUNDING BRASS, OR AS A TINKLING CYMBAL. For as charity covereth THE MULTITUDE OF SINS, and containeth all the commandments of the Law and the Prophets, and is called by the Apostle, THE FULFILLING OF THE LAW; so also this Vestment wandereth over all, and doth enclose and contain all other Vestments within itself.
2. Of charity also the Apostle saith, YET SHOW I UNTO YOU A MORE EXCELLENT WAY. THOUGH I SPEAK WITH THE TONGUES OF MEN AND OF ANGELS, AND HAVE NOT CHARITY, I AM NOTHING. And again, THOUGH I HAVE ALL FAITH, SO THAT I COULD REMOVE MOUNTAINS, AND HAVE NOT CHARITY, I AM NOTHING. The Chasuble, moreover, is the wedding-garment spoken of by the Lord in the Gospel, FRIEND, HOW CAMEST THOU IN HITHER, NOT HAVING ON A WEDDING-GARMENT? Without this, the Priest may never discharge his office, for it beseemeth him ever to abide in the bond of charity.
The Amice goeth round the mouth of the Chasuble, which meaneth that good works ought always to have charity for their source and end. For THE END OF THE COMMANDMENT IS CHARITY OF A PURE HEART, AND OF A GOOD CONSCIENCE, AND OF FAITH UNFEIGNED. And the dividing of the Chasuble into two parts, hack and fore, signifieth the two arms of charity, wherewith it reacheth unto God, and to thy neighbour, as in that scripture, THOU SHALT LOVE THE LORD THY GOD, AND THY NEIGHBOUR AS THYSELF; ON THESE TWO COMMANDMENTS HANG ALL THE LAW AND THE PROPHETS. Again, the wideness of the Chasuble is a figure of the breadth of charity, which reacheth even as far as our enemies; whence it is written, THY COMMANDMENT IS EXCEEDING BROAD.
3. The Chasuble hath two folds, right and left; these be the two precepts of charity, the love of God, and the love of his neighbour. Also it is folded double across the breast, which meaneth the heart, and between the shoulders, which are good works; in these parts, I say, the Chasuble is made to double upon itself, for if we ought so to show good deeds unto our neighbour outwardly, that we may keep the same within, whole in the heart before God. For we need to have charity in our heart, and in our work; both within and without. It is doubled before the breast, again, because by charity are gotten goodwill and holy thought; and between the shoulders, because by charity are borne untoward dealings of neighbours and adversaries. And it is lifted up at the arms, as when we work the good works of love: at the right arm, as when we DO GOOD UNTO THEM WHO ARE OF THE HOUSEHOLD OF FAITH; and at the left, as when our righteous dealings reach even unto our enemies.
4. Furthermore, over the arms it maketh three folds; on the right arm, as when we succor the faithful, monks, clergy, and laity; and on the left, as when we minister to the needs of unbelievers, that is, bad Christians, Jews, and paynim. For well are works of righteousness symbolised by the Chasuble, according unto this scripture, LET THY PRIESTS BE CLOTHED WITH RIGHTEOUSNESS. The Priest may not put off his Chasuble while he performeth his office; for the Lord commandeth in the twenty-first chapter of Leviticus, that HE SHALL NOT GO OUT OF THE SANCTUARY, that is, out of holy things or commandments.
Further, as touching that which agreeth unto the Head, even Christ, the Chasuble of the Great Priest is the Catholic Church, concerning which the Apostle saith, AS MANY OF YOU AS HAVE BEEN BAPTISED INTO CHRIST HAVE PUT ON CHRIST. This is that Vestment of Aaron, unto whose skirt the ointment ran down: IT RAN DOWN FROM HIS HEAD UNTO HIS BEARD, AND FROM HIS BEARD UNTO THE SKIRTS OF HIS CLOTHING IT RAN DOWN. For OF THE FULNESS OF HIS SPIRIT HAVE WE ALL RECEIVED, first the Apostles, then they that are come after them.
5. The Chasuble is of one piece, and whole, and is hemmed on every side, which signifieth the unity and wholeness of the Faith. Yet when the Priest spreadeth out his hands, it is in a manner divided in two parts, back and fore; and this denoteth the ancient Church, which went before the Passion of Christ, and the new, which followeth it; for THE MULTITUDES THAT WENT BEFORE, AND THAT FOLLOWED, CRIED, SAYING, HOSANNA TO THE SON OF DAVID: BLESSED IS HE THAT COMETH IN THE NAME OF THE LORD.
This Vestment representeth also the purple robe with which the soldiers encompassed Christ, as saith John in the nineteenth chapter.