“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 underfoot.
“You are the light of the world. A town built 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 others, that they may see your good deeds and glorify your Father in heaven.
Matthew 5:13-16
I have always treated Matthew 5:13-16 as separate from the Beatitudes in the 12 verses before. The Beatitudes as a whole is a depiction of the righteousness that God desires in me. God blesses such a person, meaning that God looks upon me with favour, and implies his pleasure in seeing these attitudes in me.
What is “saltiness” in a Christian? Surely then, following from the previous verses, it is the expression of our inner righteousness, the shape of our heart that is a reflection of the shape of God’s heart.
Similarly light. In John 1, life was in Jesus and that life was the light of all mankind. What is the life in a Christian? Again, it is the redeemed life. And that life is to shine as the light of the world.
When salt has lost it’s saltiness what good is it for? What good is light that is hidden?
A Christian should show the righteousness spoken of in the Beatitudes that reveals God’s heart. If a Christian cannot show the world who God is, there is nothing more to say.
Jesus’ teaching tells me that the foundation of our evangelism must be a redeemed life, the God-shaped heart behind those Beatitudes.
If there is nothing to show, what is there to say?