Retreat involves a lot of "unlearning." That may even be the greatest task of the retreat: unlearning (or beginning the process of unlearning) things about God, prayer, service.... which may be propositionally true as far as it goes--but not true enough. Just as the revelation on Sinai was a true theophany--even though it was so far surpassed in Jesus that the old categories just couldn't hold.
The real challenge of post-retreat unlearning comes because of the tendency I have (don't know about anyone else!) to stick with the descriptions, goals or value systems that exonerate me the most; that put me in the best possible situation; that are the most likely to leave me untroubled (and unchanged)--although I have also found myself clinging to the most radical possible description or definition of prayer, or poverty, or community life--the one that expresses a perfection I cannot even pretend to (effectively leaving me just as unchanged, although this time a bit depressed).
Today's liturgy offers just the message. In the first reading, we have the great revelation on Sinai. This passage wins the Oscar for "Best Special Effects" in the Bible: the towering mountain, wreathed in heavy smoke; the trembling earth; thunder and lightning and the eerie blast of a trumpet. It works so well it has become the stereotypical image of any divine intervention. (Just check the comics section of your newspaper.) Then we get the Gospel, and Jesus telling nice little stories that nobody seems to understand. When his disciples question him about it, he tells them that they "have been given knowledge of the mysteries of the Kingdom of Heaven." Sinai is kind of like retreat time: carefully choreographed to get your attention and keep you focused. But when you leave the mountain, a new and deeper revelation is waiting for you--if you have ears to hear.