You are the salt of the earth

『Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men. Ye are the light of the world. A city that is set on an hill cannot be hid. Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house. Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.』(Matthew 5: 13-16)

Salt does not mean a role for the world, but a role for the kingdom of God in the world. As Jesus said, “you” means Israel. The Bible says in Leviticus (3:13)

 『And he shall lay his hand upon the head of it, and kill it before the tabernacle of the congregation: and the sons of Aaron shall sprinkle the blood thereof upon the altar round about.』The salt that Jesus spoke is the salt of the covenant. Salt in the Bible does not change. Covenant is an everlasting covenant. The Bible says in Numbers (18:19).

『All the heave offerings of the holy things, which the children of Israel offer unto the LORD, have I given thee, and thy sons and thy daughters with thee, by a statute for ever: it is a covenant of salt for ever before the LORD unto thee and to thy seed with thee.』

The Bible says in 2 Chronicles (13:5).『 Ought ye not to know that the LORD God of Israel gave the kingdom over Israel to David for ever, even to him and to his sons by a covenant of salt? 』 God made an eternal salt covenant to give Israel to David and his descendants. It is mentioned in 2 Samuel (7: 12-16).『And when thy days be fulfilled, and thou shalt sleep with thy fathers, I will set up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom. He shall build an house for my name, and I will stablish the throne of his kingdom for ever. I will be his father, and he shall be my son. If he commit iniquity, I will chasten him with the rod of men, and with the stripes of the children of men: But my mercy shall not depart away from him, as I took it from Saul, whom I put away before thee. And thine house and thy kingdom shall be established for ever before thee: thy throne shall be established for ever. 』

"I will set up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom." Seed means Jesus Christ. It is to say that Jesus Christ will come to the world and bear all the sins of the world. So God says, I will chasten him with the rod of men, and with the stripes of the children of men. Jesus was killed by the Jews. However, the Bible says that Jesus is king of Israel. This is the salt covenant. The salt covenant is God's covenant to send the Messiah to Israel. God's salt covenant includes Jesus' crucifixion.

When Jesus says,“Ye are the salt of the world,” it represents God's covenant with Israel. God made Israel a model for all peoples. After all, the salt covenant is God's promise to all humans as well as to Israel. Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men. (Matthew 5:13) The salt used for food does not lose its salty taste. But the meaning behind of losing saltiness in the Bible is "to be dry and meaningless."

God's covenant was meaningless to Israel. Israel has broken God's covenant. Israel crucified and killed the Messiah and rejected God's promise. Because salt loses taste, it is thrown out and trodden down by people. That is why Jesus is speaking the New Covenant. God gave the new covenant, and all who cannot enter it will be left out. Unless we die in union with Jesus Christ, we cannot enter into the new covenant.

You are the light of the world, the light of this world is the light in Genesis (1: 3).『 And God said, Let there be light: and there was light. 』Since the world is in darkness, God shines light. Originally, the true light is Jesus Christ. Says in John (1: 5). “And the light shineth in darkness; and the darkness comprehended it not.”God sent Jesus Christ to the world in darkness to be light. However, many people in the world do not know who Jesus is.
The Bible says in John (1: 9-13).

『That was the true Light, which lighteth every man that cometh into the world.  He was in the world, and the world was made by him, and the world knew him not. He came unto his own, and his own received him not. But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name: Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.』

The Bible says in Ephesians (5:8). "For ye were sometimes darkness, but now are ye light in the Lord: walk as children of light"
We too were in darkness, and because of Jesus Christ, our old man dies with Jesus Christ, so that we too become light in Christ.

Bible says in Isaiah (42:6-7).『I the LORD have called thee in righteousness, and will hold thine hand, and will keep thee, and give thee for a covenant of the people, for a light of the Gentiles; To open the blind eyes, to bring out the prisoners from the prison, and them that sit in darkness out of the prison house.』This is the word of promise that God will send the Messiah to save those in darkness. Those who are trapped in darkness are those who have left God. The Bible says in John (12: 35-36).

『Then Jesus said unto them, Yet a little while is the light with you. Walk while ye have the light, lest darkness come upon you: for he that walketh in darkness knoweth not whither he goeth. While ye have light, believe in the light, that ye may be the children of light. These things spake Jesus, and departed, and did hide himself from them.』

Those who enter into Christ can shine light. But before that time it was in darkness, and no light could shine. Jesus said, "Ye are the light of the world." Jesus did not tell those who are in Christ to become light, but declared it to be light. We cannot be light ourselves. However, in many churches today, let's become light. People cannot become light on their own, but people say, "Let's become light." When we are in Christ, it is light, but people pray to become light. In other words, it is the prayer of the unborn. Those who are born again in Christ have already be light.

The Bible says in Matthew (5:16).『Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven. 』 Here, your good works is to bring those who have left God back to God. It may be necessary to do things to change the world, but ultimately to glorify God is to bring back those who have left God.

The Bible says in Acts (26: 17-18).『 Delivering thee from the people, and from the Gentiles, unto whom now I send thee, To open their eyes, and to turn them from darkness to light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith that is in me.』 God is glorified as you lead those who are in darkness to God.