Sometimes referred to as the "Divorce Passage" of the Sermon on the Mount, this week we hear about Jesus' concern for how that community lives together in a way that will uplift everyone.
To describe why it’s difficult to know the true meaning, each of these metaphors on their own are awkward for different reasons. Salt doesn’t really lose its saltiness. A city on a mountain as a light is not very practical other than to be seen from far away. You don’t usually keep a lamp/light burning forever and it will need to be extinguished at some point. These few verses don’t fully function as parables. They are more proverbial. Ultimately, holding onto Matthean themes and Matthew’s narrative may be the best help for our understanding.
Today’s text is a continuation of a long apocalyptic/eschatological section in chapter 24. Throughout the gospel, but especially in this section, Matthew is channeling a prophetic voice that calls people to repentance and promises the “day of judgment.” More than any other Gospel, Matthew portrays Jesus as a prophet like Moses and Isaiah. And like a prophet, Jesus speaks of the day of judgment that is to come, calling for repentance… or else.