Amos 6:12

Shall horses run upon the rock - First, they could not do it, because they were unshod; for the shoeing of horses with iron was not then known. Secondly, If they did run on the rock, it would be useless to their owner, and hurtful to themselves. Thirdly, And it would be as useless to plough on the rock with oxen; for there it would be impossible to sow with any advantage. Fourthly, Just as useless and injurious would it be to put gall in the place of judgment, and hemlock in the place of righteousness. You have not only been laboring in vain for yourselves, but you have also been oppressive to others; and for both ye shall suffer.

The two images both represent a toil, which people would condemn as absurd, destructive, as well as fruitless. The horse's hoofs or his limbs would be broken; the plowing-gear would be destroyed. The prophet gains the attention by the question. What then? they ask. The answer is implied by the for, which follows. Ye are they, who are so doing. As absurd is it to seek gain from injustice and oppression, to which God had annexed loss and woe, temporal and eternal. More easy to change the course of nature or the use of things of nature, than the course of God's Providence or the laws of His just retribution. They had changed the sweet laws of "justice" and equity "into" the "gall" of oppression, and the healthful "fruit of righteousness," whereof they had received the seed from God, into the life-destroying poison of sin. Better to have "plowed" the rock "with oxen" for food! For now, where they looked for prosperity, they found not barrenness, but death.

Others understand the question as the taunt of unbelievers, trusting in the strength of Samaria, that when horses should run on their rocky eminence, or the oxen plow there, then might an enemy look for gain from investing the hill of Samaria. "Shall things which are against nature be done?" "Yes," the prophet then would answer, "for ye have done against nature yourselves. Ye, have "changed justice," the solace of the oppressed, "into wormwood," the bitterness of oppression. Well may what ye think above the laws of physical nature be done, when ye have violated the laws of moral nature. Well may the less thing be done, your destruction, secure as by nature ye seem, when ye have done the greater, violating the laws of the God of nature." Amos, however, when he refers to the sayings of the unbelievers, distinguishes them from his own.

6:12 Shall horses - If prophets exhort or advise, it does no more good than if you would run your horses upon the precipices of rocks.