The Gospel told us that Jesus taught in parables, and only in parables; and that might have you asking why he had to use that round-about method, rather than his just coming out and saying what needed said.
One: through today’s first parable he explained why it is that sinful and immoral people seem to be just as prosperous as people who keep all the rules.
Second: he assured us that even a very little act of kindness might so deeply impress a sinful person that it will thoroughly change him for the better.
Third, he was saying that we should not just stick to our holy ways while isolating ourselves from those who could lead us astray.
Now, those three lessons will go in one ear and out the other, but that field with the weeds growing up with the wheat, that flourishing mustard seed, and that yeast lifting up all the dough around us – they will stay with us, causing us to lead better lives.