Living here in Africa, we are often reminded of salt and its importance in this culture. Workers request a portion of their pay in salt. When one is presented to a chief, it is important to bring a gift of salt. Recently, a widow in our church was given a gift of salt by the congregation. People here eat the bland-tasting manioc root as the principle part of their diet.
Salt makes even the humblest meal more enjoyable and tasty.
In affluent western culture, salt has lost its importance as a food taste enhancer, food preservative, and form of monetary exchange. We even avoid salt as a risk to our hearts and blood pressure. Manufacturers add excess salt to most of their products because it is cheap and adds weight to the product. To really understand the passage from Matthew, one has to have an African veneration of salt. When Jesus says that we Christians must be like salt, He is telling us that we must be of great use and value in society.