Saint Basil the Great

Of the dogmas and messages preserved in the Church, some we possess from written teaching and others we receive from the tradition of the apostles, handed on to us in mystery. In respect to piety, both are of the same force. No one will contradict any of these, no one, at any rate, who is even moderately versed in matters ecclesiastical. Indeed, were we to try to reject unwritten customs as having no great authority, we would unwittingly injure the gospel in its vitals; or rather, we would reduce the Christian message to a mere term.

-- Saint Basil the Great