Nicene and Post-Nicene Fathers, Vol. II:
On Christian Doctrine: Chapter 9

Chapter 9.—Who is in Bondage to Signs, and Who Not.

13.  Now he is in bondage to a sign who uses, or pays homage to, any significant object without knowing what it signifies:  he, on the other hand, who either uses or honors a useful sign divinely appointed, whose force and significance he understands, does not honor the sign which is seen and temporal, but that to which all such signs refer.  Now such a man is spiritual and free even at the time of his bondage, when it is not yet expedient to reveal to carnal minds those signs by subjection to which their carnality is to be overcome.  To this class of spiritual persons belonged the patriarchs and the prophets, and all those among the people of Israel through whose instrumentality the Holy Spirit ministered unto us the aids and consolations of the Scriptures.  But at the present time, after that the proof of our liberty has shone forth so clearly in the resurrection of our Lord, we are not oppressed with the heavy burden of attending even to those signs which we now understand, but our Lord Himself, and apostolic practice, have handed down to us a few rites in place of many, and these at once very easy to perform, most majestic in their significance, and most sacred in the observance; such, for example, as the sacrament of baptism, and the celebration of the body and blood of the Lord.  And as soon as any one looks upon these observances he knows to what they refer, and so reveres them not in carnal bondage, but in spiritual freedom.  Now, as to follow the letter, and to take signs for the things that are signified by them, is a mark of weakness and bondage; so to interpret signs wrongly is the result of being misled by error.  He, however, who does not understand what a sign signifies, but yet knows that it is a sign, is not in bondage.  And it is better even to be in bondage to unknown but useful signs than, by interpreting them wrongly, to draw the neck from under the yoke of bondage only to insert it in the coils of error.