At times the Orthodox themselves have had difficulty distinguishing custom and Tradition, but on the whole Orthodoxy knows that some traditions must be preserved while others may not be as essential. So what then is Tradition? For the Orthodox it is the faith received by the Apostles from Christ, handed down complete without addition or subtraction over two millennia, and lived out in the daily life of the church. Preserving the Tradition has been one of the distinguishing features of Orthodox Christianity. ‘Sources of Orthodox thought’ considers the ways in which the Tradition has manifested and expressed itself: from the Bible and the canons to the church fathers, saints, and worship.