Friends, on this feast day of St. Augustine, we reflect on the development of Catholic teaching. In one very real sense, the Father speaks all he can possibly speak in his Son, rightly called the Logos. There is no more to be revealed, no more to be said, than what is expressed in Jesus. Nevertheless, the fullness of that revelation unfolds only over space and time, much the way that a seed unfolds very gradually into a mighty oak.
A lively mind takes an idea, turns it over, considers it, looks at it from various viewpoints, questions it. Then, in lively conversation, that mind throws the idea to another mind, who performs a similar set of operations.
This "play of lively minds" goes on over the centuries. St. John threw the idea of the Incarnation to St. Polycarp, who threw it to St. Irenaeus, who threw it to Origen, who threw it to Augustine, who passed it to Thomas Aquinas, who shared it with Robert Bellarmine, who spoke it to John Henry Newman and others, who have given it to us.
Now, who guarantees that this process moves forward? The answer is the Holy Spirit, whom Jesus promised to the Church.