We're back in the thick of Ordinary Time and the start of summer, and we're back to hearing the parables in the Sunday Gospels. This 11th Sunday we have two parables dealing with the growth of the Kingdom of God (cf. Mark 4:26-34).
The first parable indicates the Kingdom of God doesn't come suddenly and all at once. There is a process to it: “first the blade, then the ear, then the full grain in the ear.” The Catholic Church didn't get to where it is today, over a billion members worldwide existing in structured dioceses and parishes, immediately after Pentecost. It took time. And there were setbacks and challenges along the way (there still are).