It is no longer an opposition between the a!grafa and the e!ggrafa, oral preaching and written preaching. The distinction between Tradition and Scripture here penetrates further into the heart of its subject, ranging on the one side that which is kept in secret, and for this reason must not be recorded in writing, and on the other, all that is the subject of preaching and that, once having been publicly declared, can henceforth be ranged on the side of the “Scriptures” (Grafai). Did not Basil himself judge it opportune to reveal in writing the secret of several “traditions”, thus transforming them into xhrugmata? This new distinction puts the accent on the secret character of the Tradition, by thus opposing a hidden fund of oral teachings, received from the Apostles, to that which the Church offers for the knowledge of all; hence it immerses “preaching” in a sea of apostolic traditions, that could not be set aside or under-estimated without injury to the Gospel. Even more, if one did this “one would transform the teaching that is preached (to\ xh/rugma) into a simple name”, devoid of meaning. The several examples of these traditions offered by St. Basil all relate to the sacramental and liturgical life of the Church (sign of the Cross, baptismal rites, blessing of oil, eucharistic epiclesis, the custom of turning towards the east during prayer and that of remaining standing on Sunday and during the period of Pentecost, etc.). If these “unwritten customs” (ta\ a1grafa twn e0qwn), these “mysteries of the Church(a1grafa ths  0E/xxlhsi/av musth/ria), so numerous that one could not expound them in the course of a whole day, are necessary for understanding the truth of Scripture (and in general the true meaning of all “preaching”), it is clear that the secret traditions point to the “mysterial character” of Christian knowledge. In effect, the revealed truth is not a dead letter but a living Word: it can be attained only in the Church, through initiation by the “mysteries” or sacraments into the “mystery which hath been hid from ages and from generations, but now is made manifest to his saints” (Col. I, 26).

Vladimir Lossky, “Tradition and Traditions” in V. Lossky and L. Ouspensky, The Meaning of Icons (St Vladimir’s Seminary Press, 1982). 13. 

My apologies for the messy Greek – I’ll try and learn how to do this properly soon!