When the Homily is about Immunology

Too much of a coincidence to pass up

The Violent Munkee asks in a recent comment:

"And thousands were added to the faith that day" stuff...how did that happen? Does that still occur today? I know there is a prominent and well reasoned concern today with the "genuine", but how is one to make sense of these passages?

...and though I offered a little unworthy answer, the wannabe desert father (who in fact IS a desert father) offers an unintentional answer that can be found HERE