The intersection of catechesis and liturgy in the early Church is a profound and formative aspect of Christian history, deeply rooted in both Jewish traditions and the unique developments of the nascent Christian faith. The Church Fathers, those theologians and bishops of the first centuries who shaped Christian doctrine and practice, provide an extensive witness to the ways in which instruction in the faith (catechesis) and communal worship (liturgy) were inseparably linked. From the earliest apostolic times through the Nicene and post-Nicene eras, catechesis and liturgy formed the means by which believers were initiated into the mysteries of the faith and incorporated into the ecclesial body of Christ. Christian catechesis, derived from the Greek katekhein ("to instruct by word of mouth"), was initially a process of oral teaching, modeled after Jewish rabbinic traditions but uniquely adapted to the proclamation of Jesus Christ as the fulfillment of divine revelation. The Didache, a late first-century or early second-century text also known as The Teaching of the Twelve Apostles, provides one of the earliest structured presentations of Christian instruction, including ethical precepts, baptismal rites, and Eucharistic prayers. This text, reflecting a community practice contemporaneous with or slightly after the writings of the New Testament, evidences a strong catechetical structure, rooted in moral instruction and preparation for the sacraments.