Matthew 5:13-16

You are the salt of the earth, but if salt has lost its taste, how shall its saltiness be restored? It is no longer good for anything except to be thrown out and trampled under people’s feet. You are the light of the world. A city set on a hill cannot be hidden. Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven..

Note: The three verses prior to these were about being persecuted for the sake of righteousness and Jesus; therefore, included below are some Old Testament verses about not being intimidated from “letting your light shine before others”, as well as verses about light and salt metaphors.
The word “salt” may have referred not to our modern table salt, but to a mixture of chemicals used as fertilizer. See also Luke 14:35 which refers to fitness of salt for the soil or the manure pile. Definition of the word translated as “taste“.

Similar Old Testament Verses

And those who are wise shall shine like the brightness of the sky above; and those who turn many to righteousness, like the stars forever and ever.

Daniel 12:3

Now the men of the city said to Elisha, “Behold, the situation of this city is pleasant, as my lord sees, but the water is bad, and the land is unfruitful.” He said, “Bring me a new bowl, and put salt in it.” So they brought it to him. Then he went to the spring of water and threw salt in it and said, “Thus says the LORD, I have healed this water; from now on neither death nor miscarriage shall come from it.

2 Kings 1:19-21

Listen to me, you who know righteousness, the people in whose heart is my law; fear not the reproach of man, nor be dismayed at their revilings.

Isaiah 51:7

I am the LORD; I have called you in righteousness; I will take you by the hand and keep you; I will give you as a covenant for the people, a light for the nations, to open the eyes that are blind, to bring out the prisoners from the dungeon, from the prison those who sit in darkness.

Isaiah 42:6-7

Fret not yourself because of evildoers; be not envious of wrongdoers! For they will soon fade like the grass and wither like the green herb. Trust in the LORD, and do good; dwell in the land and befriend faithfulness.

Psalm 37:1-3

he says: “It is too light a thing that you should be my servant to raise up the tribes of Jacob and to bring back the preserved of Israel; I will make you as a light for the nations, that my salvation may reach to the end of the earth.

Isaiah 49:6 “he” refers to God.

Arise, shine, for your light has come, and the glory of the LORD has risen upon you. For behold, darkness shall cover the earth, and thick darkness the peoples; but the LORD will arise upon you, and his glory will be seen upon you.

Isaiah 60:1-3

You shall season all your grain offerings with salt. You shall not let the salt of the covenant with your God be missing from your grain offering; with all your offerings you shall offer salt.

Leviticus 2:13

Ought you not to know that the LORD God of Israel gave the kingship over Israel forever to David and his sons by a covenant of salt?

2 Chronicles 13:5

Arise, shine, for your light has come, and the glory of the LORD has risen upon you. For behold, darkness shall cover the earth, and thick darkness the peoples; but the LORD will arise upon you, and his glory will be seen upon you. And nations shall come to your light, and kings to the brightness of your rising.

Isaiah 60:1-3

Scripture quotations are from The ESV® Bible (The Holy Bible, English Standard Version®), © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved.