“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 underfoot. – Matthew 5:13
Salt, light, Law, Prophets, accomplishment, and righteousness. In a span of only eight verses, Jesus refers to all of these subjects – why? What point is He trying to make? What common thread connects all of these disparate items? Taken as a whole, the one over-riding principle for these eight verses is this: Jesus, the true-light of the world, accomplishes the heavenly Father’s Law for you and, in so doing, gives you righteousness. How does this principle apply to the list of disparate items above? Salt, for instance, adds flavor. Jesus’ righteous followers (you) “are the salt of the earth.” You flavor the earth with Jesus’ righteousness through your Christ-like life. Of course, your Christ-like life is only possible because of Jesus’ righteousness. Once you lose Jesus’ righteousness (through unbelief, etc.), you will, apparently, “be thrown out and trampled underfoot.” Jesus appears to be telling you to persevere in the faith.
“You are the light of the world. A town built 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 others, that they may see your good deeds and glorify your Father in heaven. – Matthew 5:14-16
Light illuminates. It makes it possible, not just to see, but to see something. This ‘something’ happens to be Jesus [this is why He (Jesus) is the “true-light of the world”: see above]. Jesus’ righteous followers (you) “are the light of the world.” When the world sees you, they (the world) see Jesus. They (the world) see Jesus in the “good deeds” [the original language actually says “nice works,” (nice works, Christ-like works, etc.: they are the same in substance)] that you do. And, because the heavenly Father sent Jesus into the world, your good deeds (nice works, Christ-like works, etc.) “glorify your Father in heaven.” Everything that Jesus did (and does) was (and is) intended to lead mankind back to their heavenly Father. Thus, when the world sees you living a Christ-like life, they see God (i.e., Jesus) through your “good deeds”. Jesus appears to be telling you to make your righteousness (Jesus’ righteousness) visible for the world to see.
“Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them. For truly I tell you, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished. Therefore anyone who sets aside one of the least of these commands and teaches others accordingly will be called least in the kingdom of heaven, but whoever practices and teaches these commands will be called great in the kingdom of heaven. For I tell you that unless your righteousness surpasses that of the Pharisees and the teachers of the law, you will certainly not enter the kingdom of heaven. – Matthew 5:17-20
Jesus fulfills the Law and the Prophets. The Prophets foretell the coming of the Messiah. The Messiah will, according to the Prophets, fulfill the heavenly Father’s Law (among other things). Jesus is that Messiah. What the Prophets say that the Messiah will do, Jesus does. He (Jesus) not only fulfills messianic prophecy, He fulfills the heavenly Father’s Law to its (the Law’s) furthest extent. Note the language: Jesus uses the word “accomplished.” This is what Jesus does. He accomplishes the Law for you because you are unable to accomplish it for yourself. One of the last words that Jesus speaks on the cross is that “it is accomplished” [John 19:30]. He is referring not only to the heavenly Father’s Law, but also to His (the heavenly Father’s) plan of salvation. By fulfilling the heavenly Father’s Law, Jesus gives His righteousness to all who believe in Him (Jesus). This is the righteousness that you have. This righteousness is better than the righteousness of “the Pharisees and the teachers of the law”, who are only ceremonially righteous, not spiritually righteous [this is why Jesus says that the Pharisees are like “white-washed tombs” (Matthew 23:27): attractive on the outside, but dead on the inside]. Thus, a common thread of righteousness that connects the above-mentioned items.