And how long shall we draw the saw to and fro through this line, when we have an ancient practice, which by anticipation has made for us the state, i.e., of the question? If no passage of Scripture has prescribed it, assuredly custom, which without doubt flowed from tradition, has confirmed it. For how can anything come into use, if it has not first been handed down? Even in pleading tradition, written authority, you say, must be demanded. Let us inquire, therefore, whether tradition, unless it be written, should not be admitted.
Certainly we shall say that it ought not to be admitted, if no cases of other practices which, without any written instrument, we maintain on the ground of tradition alone, and the countenance thereafter of custom, affords us any precedent. To deal with this matter briefly, I shall begin with baptism. When we are going to enter the water, but a little before, in the presence of the congregation and under the hand of the president, we solemnly profess that we disown the devil, and his pomp, and his angels.
Hereupon we are thrice immersed, making a somewhat ampler pledge than the Lord has appointed in the Gospel. Then when we are taken up (as new-born children), we taste first of all a mixture of milk and honey, and from that day we refrain from the daily bath for a whole week. We take also, in congregations before daybreak, and from the hand of none but the presidents, the sacrament of the Eucharist, which the Lord both commanded to be eaten at meal-times, and enjoined to be taken by all alike. As often as the anniversary comes round, we make offerings for the dead as birthday honours.
We count fasting or kneeling in worship on the Lord's day to be unlawful. We rejoice in the same privilege also from Easter to Whitsunday. We feel pained should any wine or bread, even though our own, be cast upon the ground. At every forward step and movement, at every going in and out, when we put on our clothes and shoes, when we bathe, when we sit at table, when we light the lamps, on couch, on seat, in all the ordinary actions of daily life, we trace upon the forehead the sign.
Source: De Corona (The Chaplet) (New Advent)