Thus saith the LORD; For three transgressions of Israel, and for four, I will not turn away the punishment thereof; because they sold the righteous for silver, and the poor for a pair of shoes;
For three transgressions of Israel - the ten tribes, the main subject of Amos' prophecies.
Because they sold the righteous for silver - Israel's judges for a bribe are induced to condemn in judgment him who has a righteous cause, in violation of Deuteronomy 16:19.
The poor for a pair of shoes - literally, sandals of wood, secured on the foot by leather straps, less valuable than shoes; often, however, made beautiful and costly for the adornment of Hebrew women. Thus low did they value man, made in the image of God, that they thought needless ornament of more consequence. Compare the same phrase, for the most paltry bribe, Amos 8:6; Ezekiel 13:19; Joel 3:3. They were not driven by poverty to such a sin; beginning with suffering themselves to be tempted by a large bribe, they at last are so reckless of all shame as to prostitute justice for the merest trifle. Pusey takes it of the merciless selling of the debtor by the creditor. The law allowed the Hebrew poor to sell himself (so Leviticus 25:39; Deuteronomy 15:12, ought to be translated). But he was not to be treated as a slave, but as a hired servant or sojourner (Leviticus 25:39-40); and at the year of jubilee he was to be entirely free. The practice of selling an insolvent debtor grew up, though against the law. Still more illegal was the usage of selling the wife and children. (Compare Nehemiah 5:5; Matthew 18:25; 2 Kings 4:1). Amos convicts them of injustice, incestuous unchastity, and oppression first, as these were so notorious that they could not deny them, before he proceeds to reprove their contempt of God, which they would have denied, on the ground that they worshipped God in the form of calves.