Walter Wink’s reading of the Sermon on the Mount is the kind of exegesis that would get failed in a historical-critical Bible class. It has succeeded because it is good ethics so no one wants to point out too loudly that it’s bad exegesis.
Jesus’ teaching in the Sermon on the Mount unsettles many biblicist ways of understanding Scripture. It may even be better to move from speaking of ‘the Scriptures’ as a noun, to speaking of ‘Scripturing’ as a verb.
Jesus calls us the salt of the earth and the light of the world. What would these metaphors have meant to his first hearers?