Jesus told us to “Learn of me, for I am meek and humble of heart.”
That being so, it would hardly seem to be Christ-like for us to go around saying, “We are the salt of the earth. We are the light of the world.”
But there is one consideration that could legitimize our claim to be the salt of the earth and the light of the world. That is the realization that we have no wisdom, no knowledge, other than what has been drummed into us by highly moral elders and our learned teachers. As St. Paul wrote, “What do you possess that you have not received? But if you have received it, why do you boast as though you had not received it?” (1 Cor. 4:7)
As children we had elders who wove moral fibers into our character by repeatedly punishing us for being selfish, by repeatedly rewarding us for being selfless. You might agree with that verse from the Letter to the Hebrews, “At the time, all discipline seems cause not for joy but for pain, yet later it brings the peaceful fruit of righteousness.” (Heb. 12:11)
We each have a store of useful knowledge because we had parents and teachers who wouldn’t let us go to play before we did out homework. Christianity and civilization are like chains that carry on from generation to generation until they come to a link that doesn’t do its duty as salt of he earth and light of the world.