Jesus' litmus test

Every so often, a Gospel I've heard a bagillion times without it making the slightest impression seems to explode with meaning. That happened today as I heard, for the bagillion and first time Jesus' reminder that you can tell a tree by its fruit. A good tree cannot bear bad fruit; a bad tree cannot bear good fruit. By their fruits you shall know them.
If we were to ask Jesus for more insight, he would probably tell us (as he did, in Matthew 12, which is almost a repetition of today's Gospel) to look to the heart. People can talk up a storm and say all the right things. They can repeat orthodox teachings and say pious prayers. They can wrap themselves in a mantel of righteousness the way politicians wrap themselves in the American flag. None of that really tells you who they are. By their fruits you shall know them.
And lest we think this is Jesus' advice for judging others, we get the famous parable where Jesus specifies the "fruits" that he is talking about. We call them the Works of Mercy.
In other words, Jesus is inviting us to bear "good fruit." And he is, yes, also showing us how to recognize the signs of God's presence in people who do not speak the language or wear the signs of our faith. In this day and age, that's more vital than ever!