Here it is! My summary of the LAST chapter of my group's study, Lord, Only You Can Change Me by Kay Arthur.
In one of those neat God-timing things, we studied salt and it's uses (in our homeschool lesson) the very same week I did this chapter of our study. I love it when He does that. {grin} For instance, Roman soldiers were paid in salt! And of course salt is used to preserve things, and to flavor things."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." Matthew 5: 13-16
I love this point Kay makes here: the amount of salt in a recipe matters. That means that each and every one of us matters; our "saltiness changes the flavor of the world." But if salt loses it's flavor, it's not good for anything but to be trampled underfoot.
Another things salt does: makes you thirsty. If we are being salty enough, then our saltiness should be causing others to thirst--for God!
I learned a few things I'd never realized about Lot in this study. When the angels came to rescue him from Sodom before the town was destroyed, he had no influence with those around him. His sons-in-law laughed at him, the men of the town threatened to do vile things to him, and his wife only reluctantly followed him. His salt had lost it's flavor. But in 2 Peter 4-9, the Bible tells us that the Lord considered Lot a righteous man whose soul was tormented daily by all that went on in that town around him. And it tells us "the Lord knows how to rescue the godly from temptation..." So Kay asks us to consider: Are we being salty enough, or are we being corrupted? There is no middle ground.
Light. It has one purpose: to light the darkness. God is Light, and we must help others find their way through the dark to find Him. If a candle or lamp doesn't give light, what use is it? We need to be doing good works, but we must be careful to reflect all glory or honor back to God. It's like that saying I love, "Be the moon; reflect the Son."