II. And therefore they are in the highest degree instructive
Those days, therefore, dearly-beloved, which intervened between the Lord's Resurrection and Ascension did not pass by in uneventful leisure, but great mysteries were ratified in them, deep truths revealed. In them the fear of awful death was removed, and the immortality not only of the soul but also of the flesh established. In them, through the Lord's breathing upon them, the Holy Ghost is poured upon all the Apostles, and to the blessed Apostle Peter beyond the rest the care of the Lord's flock is entrusted, in addition to the keys of the kingdom. Then it was that the Lord joined the two disciples as a companion on the way, and, to the sweeping away of all the clouds of our uncertainty, upbraided them with the slowness of their timorous hearts. Their enlightened hearts catch the flame of faith, and lukewarm as they have been, are made to burn while the Lord unfolds the Scriptures. In the breaking of bread also their eyes are opened as they eat with Him: how far more blessed is the opening of their eyes, to whom the glorification of their nature is revealed than that of our first parents, on whom fell the disastrous consequences of their transgression.
Source: Sermons (New Advent)