What does Jesus teach us in Matthew 513?

Answer 1

Jesus said that his mission was to the nation of Israel:

Matthew 15:24 But He answered and said, "I was not sent except to the lost sheep of the house of Israel."

So the first application of Matt 5:13 must be to the nation of Israel. The analogies of salt and light reminded Israel that this was God's intention when He chose Israel as His people.

Salt speaks of hindering the spread of corruption; salt creates thirst; it brings out the flavor. So Israel was to be like seasoning to the gentile nations, serve as a preservative, and make others long for the righteousness described in the verses before verse 13.

Living as lights (Matt 5:14) the nation of Israel was to be an example of a righteous, God fearing people, to the surrounding nations.

But as salt Israel had lost its flavour.

Of course these principles can be applied to the believer today. Right living Christians can be an influence in their society and effective in spreading the gospel.

Answer 2

Jesus called his disciples the "salt of the Earth" here and warned them not to lose their saltiness. Salt was a very valuable and useful substance, and is symbolized in The Bible as making something palatable and having a preservative effect. (Numbers 18:19; Colossians 4:6)

By Jesus calling his disciples the "salt of the Earth" he was implying their value in his eyes as something precious, agreeable to him, and having the ability to preserve the life of others by teaching them about the Kingdom. It also carried the notion of a long lasting favor with him as long as they kept the qualities that make them so valuable and agreeable to him. It is a lesson for his disciple to always speak and act in "good taste" in order to better reach others with the message. He warned if his disciples didn't do this, they would lose this "salt-like" quality and not be useful anymore.