What do you think the Great Commission is?
Jesus having established His Church on the Rock of Peter empowered the Church to continue His mission when He said:
“Full authority has been given to me both in heaven and on earth; go, therefore and make disciples of all the nations. Baptize them in the name of the Father, and of the Son, and of the Holy Spirit. Teach them to carry out everything I have commanded you. And know that I am with you always, until the end of time. “(Mt. 28:18-20)
Catechesis is nothing other than the process of transmitting the Gospel, as the Christian community has received it, understands it, celebrates it, lives it and communicates it in many ways. Scripture, Tradition, Practice, Ritual, and Revelation, they all form an organic whole. Deviations are heresies pure and simple.
Check out: Hillaire Belloc’s “The Great Heresies.”