Jesus uses the familiar metaphors of salt and light to describe the life of discipleship. We take salt and light for granted in our society, but these commodities were more precious in ancient cultures. Just as now, salt was used in Jesus’ time for flavoring, as a preservative, and as a healing agent. Similarly, the widespread use of electricity in the modern world makes us less aware of the value and importance of light. Jesus’ call to be salt for the earth and light for the world powerfully states our mission as Church and as Christians.

This is given more concrete expression as the Corporal and Spiritual Works of Mercy. When we feed the hungry, clothe the naked, console those who mourn, and so on, we show ourselves to be the salt of the earth and the light of the world. When we do these things with the community of faith, the Church, we are indeed acting as “a city set on a mountain” that cannot be hidden!