Collectively, those things are the very opposite of political clout and partisan power. Jesus is describing people who are willing to be oppressed and disenfranchised for the sake of true righteousness. They are peacemakers, not protestors; poor in spirit, not affluent and distinguished; people who are persecuted, not the pompous and the power mongers.
And yet, notice. These poor and oppressed people are the ones Jesus is addressing when he says in Matthew 5:13 "You are the salt of the earth"—and in verse 14, "You are the light of the world." He begins addressing them directly in verse 11: "Blessed are you when others revile you and persecute you and utter all kinds of evil against you falsely on my account. Rejoice and be glad, for your reward is great in heaven, for so they persecuted the prophets who were before you."
To whom is he speaking? The believers in His audience, those who exemplify the traits He blesses in the beatitudes. Those who were persecuted for righteousness' sake. Those who were reviled for His Name's sake. They were for the most part simple, common people—everyday people from among "the multitudes" (v. 1).
Verses 13-14 are declarative: "You are the salt of the earth. . . . You are the light of the world." The only imperative in this context is verse 16: "let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven."
In other words, Jesus was not commanding His followers to be salt and light. He was saying that if you are a true believer, you are salt and light. He's urging us not to lose our savor or hide our light. Salt is what it is by nature. Light is what it is by nature. You can contaminate salt or hide light, but you can't make sand into salt or turn a stone into a candle. So He doesn't "command" us to "be salt"; He says we are salt and cautions against losing our savor. He doesn't command us to be light; He says we are light and forbids us to hide under a bushel.
And what is supposed to happen when we let our light shine before men? They see our good works and glorify God. This is not about wielding political clout. It's not about organizing protests against ungodliness. It's about how we live—the testimony of our lives. It's about exemplifying the same traits Jesus blessed in the beatitudes. That's how we let our light shine, and that's the saltiness we inject into an otherwise decaying and tasteless society.
Christ has made us different from the world, and we should simply be what we are. We're salt in a decaying and tasteless culture, and we're light in a dark world. If we give up (or cover up) what makes us distinctive, we lose our savor and forfeit our only real influence. If we have to squelch the heart of the message Christ has called us to proclaim in order to advance some political or moralistic agenda, we're guilty of hiding our light under a bushel. Those who think the church can have a greater influence by adopting a worldly strategy are actually undermining the only valid influence Christians can have on society.