Scripture & Tradition
Sacred Tradition
Divine revelation comes to us through both Scripture and the living Tradition handed on by the apostles, two modes of one deposit of faith.
Catholic teaching
Sacred Tradition is not human custom but the apostles' oral teaching, worship, and practice, faithfully handed down and authoritatively interpreted by the Magisterium. Scripture itself arose within, and presupposes, this living Tradition.
Biblical foundation
Paul explicitly commands the Thessalonians to hold fast to traditions taught 'either by word of mouth or by letter,' placing oral and written transmission on equal footing. John notes that not everything Jesus did was written down.
Scripture references
Historical evidence
St. Basil the Great in the fourth century catalogued numerous universally accepted practices, such as the sign of the cross and facing east in prayer, that come from unwritten apostolic Tradition rather than Scripture alone.
The Church Fathers
“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.”