Salt of the earth” is one of the best-known phrases in the Bible, but it’s more enigmatic than we realize. Salt has many qualities, and it’s not clear which one Jesus is highlighting. Does Jesus want disciples to preserve the world? Are disciples as necessary to the world as salt is to life? Are disciples the seasoning on a main course dished up by someone else?
We get a clue from the oddity of the phrase. Jesus’s disciples are not salt on food, ice, or sacrifice. Disciples are salt on the land, and that juxtaposition is more threatening than reassuring.
Yahweh’s destruction of Sodom and Gomorrah left behind a proverbial wasteland of salt. When Israel broke covenant, Moses warned that the Lord would make the land “brimstone and salt, a burning waste, unsown and unproductive, and no grass grows on it, like the overthrow of Sodom and Gomorrah, Admah and Zeboiim” (Deut. 29:23; cf. Ps. 107:34). Salting farmland was a tactic of war, a way of cutting off an enemy’s food supplies. Abimelech sealed his victory over the city of Shechem by sowing it with salt (Judg. 9:45), and the Romans salted Palestine during the Jewish War of the late 60s a.d.
Jesus wishes to cast fire to the earth (Lk. 12:49), and his disciples fulfill that desire. When he scatters his salty disciples, the world becomes a wasteland.
Why would Jesus want to do that? Throughout the Gospels, Jesus has severe words for the Jewish leaders. They are hypocrites who close the kingdom of heaven. They are Pharaohs who lay burdens on the people. They are graves that spread impurity, petty tithers who neglect justice and mercy, murderers of prophets (Matt. 23). This is the fruit Jesus came to destroy. We can generalize: When a nation’s chief domestic product consists of greed, lust, oppression, cruelty, and lies, it needs to be salted until every green thing has withered.
Jesus annihilates the world’s harvest by sending out salty disciples who obey his commandments. When they fulfill Torah as Jesus does, disciples can’t help but choke out poisonous fruit. Jesus commands his disciples to resist the world’s desires, values, and habits. When Christians follow Jesus’s commands, they undo evil habits. We avoid escalating insults that lead to murder; we also nip the escalation in the bud by pursuing reconciliation. We don’t simply renounce vengeance but offer our left cheek to receive the second slap, suffering rather than dealing out revenge. We aren’t allowed to be indifferent to enemies but must love them, undercutting hostility. When disciples obey, hatred and violence have no traction.
When Jesus talks of a “righteousness that surpasses that of the scribes and Pharisees,” he doesn’t mean that he applies more and stricter rules, nor is he calling for more rigorous enforcement. As Glen Stassen has pointed out, he’s commanding his disciples to enact a redemptive righteousness that unravels cycles of sin.
We might naively hope that the world would welcome salt-of-the-earth types who are committed to reconciliation, faithfulness, truth-telling, love, and piety. But some worlds are built on vengeance, lust, and hatred; some churches are energized by hostility toward other churches. Some religions turn piety into an honor competition. Such religions and worlds naturally see serious Christians as a threat to their way of life, because Christians are a threat to their way of life. Where mutual hatred determines the structure of social life, lovers are dangerous. Anyone who reaches across the barricades to bless an enemy is tampering with the way the world is, and ought to be. In a world such as ours, where virtually every sexual desire demands respect, disciples who urge the lustful to pluck out their lecherous eyes aren’t just prudes, but dangerous prudes. In a world of lies, truth-tellers must be silenced. It’s no accident that Jesus calls his disciples “salt of the earth” just after telling them they should expect to be persecuted.
Here the image of salt develops into something more positive. Salt is added to Israel’s sacrifices, and disciples are salt in this sense, too. The world is an altar. Humanity and the world are to become a single great offering to God. As we offer ourselves in obedient, suffering self-sacrifice, we become the seasoning on a cosmic sacrifice that makes it well-pleasing to God.
Jesus’s proverb is primarily a warning about unsaltiness. If we are like the foolish man who hears Jesus but doesn’t do what he says, our house will collapse before the wind and the rain. When the fruit of the Church is no better than the harvest of the world, when we’re as hateful, vengeful, competitive, and greedy as everyone else, we’ve become unsalty salt, good for nothing “except to be thrown out and trampled underfoot by men.” Then we ourselves, the salt of the earth, must be salted with salt.