There are those who turn justice into bitterness and cast righteousness to the ground. He who made the Pleiades and Orion, who turns midnight into dawn and darkens day into night, who calls for the waters of the sea and pours them out over the face of the land—the LORD is his name. With a blinding flash he destroys the stronghold and brings the fortified city to ruin.
There are those who hate the one who upholds justice in court and detest the one who tells the truth. You levy a straw tax on the poor and impose a tax on their grain. Therefore, though you have built stone mansions, you will not live in them; though you have planted lush vineyards, you will not drink their wine. For I know how many are your offenses and how great your sins.
There are those who oppress the innocent and take bribes and deprive the poor of justice in the courts. Therefore the prudent keep quiet in such times, for the times are evil. Seek good, not evil, that you may live. Then the LORD God Almighty will be with you, just as you say he is. Hate evil, love good; maintain justice in the courts. Perhaps the LORD God Almighty will have mercy on the remnant of Joseph.
Amos 5:1-15 (NIV). That's the positive message of the chapter, of course. People forget that whenever Martin Luther King, Jr. quoted the famous verse (from later in the chapter), "Let justice roll down like waters and righteousness like an everlasting stream," it's not a nice, encouraging sentiment: it's a divinely backed threat against those who commit injustice. That was Amos's point: divine punishment is coming against the unjust like an unstoppable and devastating flood of water. And, of course, King knew this quite well: his view was that the preacher against injustice must be Amos, full of fire and willing to tell people that God will punish them for their sins. Our culture continually tries to sanitize King's message so that it's a feel good message of hope. But he was out to make the unjust feel the judgment of God breathing down their back if they did not change their ways. The hope came from the judgment: judgment for the oppressor is always hope for the oppressed.
