Walk through Amos, verse by verse, with the great Bible Commentaries of Matthew Henry (1662 - 1714) & Adam Clarke (1760 - 1832)
6:12
Shall horses run upon the rock? will one plow there with oxen? for ye have turned judgment into gall, and the fruit of righteousness into hemlock: KJV
{Whether horses may run in stones, either it may be eared with wild oxen? For ye turned doom into
bitterness, and the fruit of rightwiseness into wormwood. } Wycliffe's Bible
The methods used for their reformation had been all fruitless and ineffectual: Shall horses run upon the rock, to hurl or harrow the ground there? Or will one plough there with oxen? No, for there will be no profit to countervail the pains. God has sent them his prophets, to break up their fallow-ground; but they found them as hard and inflexible as the rock, rough and rugged, and they could do no good with them, nor work upon them, and therefore they shall not attempt it any more. They will not be reclaimed, and therefore shall not be reproved, but quite abandoned.