Jesus has begun his teachings on the kingdom of God. He focused on our attitudes and actions (vs. 3-12) and on our impact in the world (vs. 13-16). Yet, so far, not once has Jesus mentioned the law, or keeping the law, or even the interpretation of the law.

He wants to be clear that he is not attacking or abolishing what has come before; in fact, he is fulfilling it. Taken together, the “Law” and the “Prophets” represent the whole of the Old Testament. The meaning of the Old Testament is completely fulfilled in Jesus – Scripture has Jesus as its core, pointing to him. Jesus’ teaching deepens the meaning of the law, revealing a deeper ethical standard. Jesus’ actions reveal in a greater way the prophetic teachings.

We must also remember that Jesus’ death on the cross also fulfilled the law. We see in the cross the penalty for breaking the law; we see Jesus bearing the penalty for all who are saved. The law teaches and trains us, but it also points out the worthlessness of our own efforts to gain righteousness before God. “In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace.” (Ephesians 1:7 ESV)

Grant Osborne in his commentary on Matthew says one of the applications we learn from Matthew 5:13-16 is that discipleship is always active. Being salt and light is not only witnessing or confronting evil but a lifestyle full of “good works,” always helping, always demonstrating God’s love and concern for the world. Focusing on salt’s ability to flavor, as we act as salt, we let others taste the goodness of God. As a visible city or a lamp on a stand, we let others see the goodness of God.

That’s why Jesus’ words about salt imply a judgment. Jesus does not want a useless disciple, one so diluted or polluted by the world, that our effectiveness as salt is gone. We are only fit for the garbage heap if that’s how we are! True discipleship is distinguished by the number of people affected by it.

Jesus is also calling us to a visible discipleship. The city is not hidden; the lamp is not under a basket; the light shines before others. We cannot follow Jesus in a purely private way and think we are behaving as citizens of the kingdom. Dietrich Bonhoeffer said in his book Discipleship, “Any community of Jesus which wants to be invisible is no longer a community that follows him.” We shine before others so that others may see our good works and give glory to our Father.

“Fulfilling this plan [to be salt and light] will demand that the whole of our lives be whole-heartedly and unceasingly devoted to him and to his service. That devotion will cost us everything.” (Sinclair Ferguson)

I wonder what Jesus’ disciples thought when he told them that they were to be the salt “of the earth” and the light “of the world.” Were they shocked that Jesus told them to begin thinking and acting beyond the borders of Israel? Maybe they thought of God’s conversation with Abram from Genesis 12: “I will make of you a great nation, and I will bless you and make your name great, so that you will be a blessing…. in you all the families of the earth shall be blessed.” Jesus seems to be anticipating their mission into the world (and our mission still).

The disciples may have still been thinking about Jesus’ teaching on suffering. That could have been a big surprise for them! They did not yet grasp that they were following a Messiah who would suffer, who would be crucified.

Jesus is still telling us that we are salt and light. What are we doing to take on the world, to expand our own borders?