The Word of God IS NOT Locked Away In Writing
From the recent Vatican Synod on the Word of God:
In view of the Word of God who is the Son-Incarnate, the Father spoke in times past through the prophets (cf. Heb 1:1). Through the power of the Spirit, the Apostles continue to proclaim Jesus and his Gospel. Thus, the Word of God is expressed in human words in the proclamation of the prophets and Apostles.
e. Sacred Scripture is the message of revelation written down under divine inspiration. As such, it can truly be said to be the Word of God (cf. DV 24) which is entirely focused on Jesus, because "it is they [the Scriptures] that bear witness to me" (Jn 5:39). Through the charism of divine inspiration, the Books of Sacred Scripture have a direct, concrete power of appeal not possessed by other texts or human discourses.
f. But the Word of God is not locked away in writing. Even though Revelation ended with the death of the last apostle(cf. DV 4), the Word-Revealed continues to be proclaimed and heeded throughout Church history. The Church has the responsibility to proclaim the Word to the whole world as a response to its need of salvation. In this way, the Word continues its course through vibrant preaching and its many forms of evangelization, where proclamation, catechesis, liturgical celebrations and the service of charity hold a high place. Preaching, in this sense, under the power of the Holy Spirit, is the Word of the living God communicated to living persons.
g. Like fruit coming forth from its roots, the truths of the Church’s faith, in the fields of dogma and morality, fall within the sphere of the Word of God.
From this vantage point, when God’s Revelation is proclaimed in faith, it becomes a real moment of Revelation, which can truly be called the "Word of God" in the Church.
Catholic Christians are not "people of the book" but people of the Word of God which encompasses more than the Bible as the sole source of revelation. If the Word of God was limited to what was written in the pages of Scripture canonized in 393 AD, then did the Church flounder for almost 4 centuries without the official Bible? Then, what about the next 1100 years after that until the printing press was invented and Scripture became more readily available to the minority of the population who were literate? Did those other Christians live without the Word of God? Obviously not! They lived by the Word of God found in preaching, teaching and the liturgy of the Catholic Church, where the proclamation of the Word of God continues to this day.
If you get a chance, the Bishop's Synod writing of Instrumentum Laboris on the Word of God in the life and mission of the Church makes for some interesting reading.