Isaiah 1:21

"How is the faithful city become a harlot! she that was full of justice! righteousness lodged in her, but now murderers. Thy silver is become dross, thy wine mixed with water. Thy princes are rebellious, and companions of thieves; everyone loveth bribes, and followeth after rewards: they judge not the fatherless, neither doth the cause of the widow come unto them."

This is further lament over the extensive apostasy of Jerusalem. The message of Isaiah here is very similar to that repeated so frequently in practically all of the twelve minor prophets. Social justice simply did not exist any longer in Israel nor in Judah. Israel had, at the times of Isaiah, just about filled up the cup of their wickedness. They had become "traffickers," that is Canaanites, meaning that they were at that time no better than the godless Canaanites whom God had driven out of Palestine in order to re-populate the land with Israel. At this period in their history, the time was as when God would remove them from what, at one time, had been "their land." Israel at that point fully deserved to be removed from Palestine. Why then did God spare "a remnant," bring them back from Babylon and repatriate them in Palestine? There can be but one answer. Due to the Divine promises to the great patriarchs of Israel's history, God had no honorable course except to retain his watchfulness over the apostate nation till Messiah should come, fulfilling the ancient promises.

See my comment in Vol. 2 of the commentary on the Minor Prophets, p. 198.