Today's Gospel is the one where Jesus tells his disciples that they are the salt of the earth and the light of the world.
Once I went to a talk by a Biblical scholar who specialized in studying the cultural life of the ancient world. He explained this parable in a way I had never heard of, but made so much sense.
In Jesus' day, he said, people did not use salt primarily in food. It was a hot climate with difficult access to water. Instead, they used it as part of their fuel for cooking. In what way?
This is the interesting part. They used "cakes" made out of animal dung for fires and cooking. And they put salt into these dung cakes to act as a catalyst. The salt made them catch fire easily.
So Jesus is really telling us that to be like salt, we need to be like the spark that sets the world on fire, on fire with love of God and neighbor.
In this context, the next image makes more sense: "You are the light of the world." We are the light because first, we are the salt that makes the fire burn.