Being Salt and Light in the world.

You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled by men.  “You are the light of the world. A city on a hill cannot be hidden. Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. In the same way, let your light shine before men, that they may see your good deeds and praise your Father in heaven. Mt 5:13-16

1. You are the salt of the earth. �By beginning with You, Jesus emphasises to the disciples that they have both the calling and the responsibility to be influencers in the world.   Salt is a number of effects :
as a seasoning agent, it improves the taste of the food that it comes into contact with, and so as we come into contact with society our Christian values should improve the nature of that society.
salt makes people thirsty - and as Christians we seek to create a thirst in people's lives that can only be satisfied by Jesus, who said : "if anyone is thirsty, let him come to me  me and drink" (Jn 7:37)
Salt is used to thaw ice on roads : so it can have the effect of warming hearts that have hardened against the gospel - over time the saltiness of Christians can bring people to know Jesus Christ.
as a preservative, salt gives food an improved length of life. Ultimately, with enough salt, those who do know Jesus, and acknowledge Him as Lord and Saviour will have eternal life.

2. Salt which loses its saltiness is useless. � Jesus' teaching is challenging.  There is little room for those who are Christians, but who have lost their saltiness, or their "edge".  Without the testimony of lives lived out with integrity and consistency with the principles that Christians claim to follow, the testimony of our lips is useless.  But be clear : this does not require us to be perfect : knowing our sinfulness, and knowing our need to confess it and be cleansed of it is a vital part of the Christian gospel. Then, as v16 says, "let your light shine before men, so that they may see your good deeds and praise your Father in heaven."

3. You are like light for the world. � Light shines on dark things and exposes what is there. This is a call to the church to challenge evil within our society, however uncomfortable this may be. Having humility and servanthood within our character does not make us toothless and wishy-washy.  The light that we bring, is not our own light - it is not who we are in ourselves, but rather the light of God shining through our lives as the Holy Spirit works through them. This doesn't mean that we have to refer to God in every other sentence, but when the opportunity arises, we can share with another person the light that God has given us. 

4. Don't hide your light. � We hide our light when we stay silent in the face of discussion which is contrary to that which we believe. We hide our light when we fail to accept and conform with behaviours that are not in line with Jesus' teaching. We hide our light when we don't care for the needs of others, and walk by on the other side : since we have missed an opportunity to let the light of Jesus' compassion shine out in acts of kindness.  If we let the light of the Holy Spirit at work in us shine through, then we bring glory to God, and there can be no greater joy than being able to give glory to the Father as we go through our daily lives.