The word "tradition" is taken from the Latin trado, tradere, meaning "to hand over, to deliver, to bequeath". The teachings of Jesus Christ and the holy Apostles are preserved in writing in the Scriptures as well as word of mouth and are handed on. This perpetual handing on of the Tradition is called the Living Tradition; it is the faithful and constant transmission of the teachings of the Apostles from one generation to the next. That "includes everything which contributes towards the sanctity of life and increase in faith of the People of God; and so the Church, in her teaching, life and worship , perpetuates and hands on to all generations all that she herself is, all that she believes." The Deposit of Faith (Latin: fidei depositum) refers to the entirety of Divine revelation. And there is, according to Roman Catholic theology, two sources of Revelation which constitute a single Deposit of Faith, meaning that the entirety of Divine Revelation and the Deposit of Faith is transmitted to successive generations in Sacred Scripture and Sacred Tradition (through the teaching authority and interpretation of the Church's Magisterium (which consists of the Church's bishops, in union with the Pope), typically proceeding synods and ecumenical councils).
In Orthodox theology, Holy Tradition is the inspired revelation of God and catholic teaching (Greek katholikos, "according to the whole") of the Church, not an independent source of dogmatic authority to be regarded as a supplement to biblical revelation. Tradition is rather understood as the fullness of divine truth proclaimed in the scriptures, preserved by the apostolic bishops and expressed in the life of the Church through such things as the Divine Liturgy and the Holy Mysteries (Eucharist, baptism, marriage, etc.), the Creed and other doctrinal definitions of the Seven Ecumenical Councils, canonical Christian iconography, and the sanctified lives of godly men and women.
According to the theological understanding of these Churches, sacred scripture is the written part of this larger tradition, recording (albeit sometimes through the work of individual authors) the community's experience of God or more specifically of Jesus Christ. Thus, the Bible must be interpreted within the context of sacred tradition and within the community of the church. That is in contrast to many Protestant traditions, which teach that the Bible alone is a sufficient basis for all Christian teaching (a position known as sola scriptura).
In the English language, "sacred tradition" is more likely to be used in reference to Catholicism and "holy tradition" in reference to Eastern Orthodoxy, although the two terms are interchangeable in meaning.
Among the earliest examples of the theological appeal to tradition is the response of early 'orthodox' Christianity to Gnosticism, a movement that used some Christian Scripture as the basis for its teachings. Irenaeus of Lyons held that 'rule of faith' (regula fidei) is preserved by a church through its historical continuity (of interpretation and teaching) with the Apostles. Tertullian argued that although interpretations founded on a reading of all Holy Scripture are not prone to error, tradition is the proper guide. Athanasius held that Arianism fell into its central error by not adhering to tradition.