You are the salt of the earth

Oh, she is the salt of the earth, we often say when we are referring to a person who is straightforward, honest and without guile. In the words of another saying, 'what you see is what you get'. In today's reading, Jesus' description of his disciples as 'the salt of the earth' would have struck a chord and meant something very specific to his listeners. In Jesus' day salt was a valuable commodity. In order to preserve food from decay in the heat, salt was applied as a preservative. It also served to enhance the flavor of the food. The ancient tradition of salting the sacrificial offerings (Ezek.43:24) denoted a purifying function; it was perhaps for this reason that newborn babies were rubbed with salt to denote purification of the addition to God's people and as a reminder of the covenant.
 Those who heard Jesus speak would have understood the meaning and tradition behind the idea of being 'salt of the earth'. In the same way as salt prevents decay and corruption, so the witness of Christians, who live a life in the power of the Holy Spirit, protects the world and society from decay and corruption. It also adds much-needed flavour to society. Too much salt in our food can make us thirsty. St Augustine once wrote, 'O Heavenly Father, you have put salt in our mouths that we may thirst for you.' The work of the Holy Spirit is to create within us a thirst for the things of God: for union with God, for communion with him and for grace to live a life which is holy and pleasing to him.
Jesus also calls us to be 'the light of the world' . In this way we are to be like our Master, for in John 8:12, Jesus describes himself as 'the light of the world'. We are to be countercultural, signs of contradiction, heralds of the gospel of life in a world which, in so many respects, has lost its way. St. Joseph the Worker Parish

 (excerpt catholic-bible-school)