This article reveals and substantiates the direct link between the sacraments and catechesis. The author examines the evidence from the Holy Scriptures, as well as patristic and liturgical sources, and shows with examples that baptism, chrismation and participation in the Eucharist are preceded by a person’s acceptance of the Word of God. We find evidence of this in the Acts of the Apostles, the Didache, the Apologies of St. Justin the Philosopher, Origen homilies, etc. The author compares in detail the two descriptions of the baptismal and Sunday liturgies in the First Apologia of St. Justin the Philosopher (2nd century), from which it is clear that catechesis preceding baptism serves the same purpose as the biblical readings at the Liturgy of the Word before the Eucharist. The early Christian sources note the complementarity of the perception of the Word of God and the perception of the eucharistic substances, as well as the impossibility of considering them to be self-sufficient and independent of each other. Origen and St. John Chrysostom consider the conscious perception of Christian teaching and the communion of the eucharistic Mysteries as a double and inseparable form of communion with God. The catechisms of St. John Chrysostom and St. Cyril of Jerusalem (4th century) emphasize that the homily should contain relevant teaching for the life of the catechumens, and not simply be a moment for theoretical reflection. The catechetical word is addressed to people who want to make certain commitments as they enter the Church, and this word changes them from the inside out and converts them. On the other hand, the Word of God is deeply liturgical and cannot be studied in isolation from the service of worship in the church.