John Calvin Commentary Isaiah 28:25

"When he hath levelled the face thereof, doth he not cast abroad the fitches, and scatter the cummin, and put in the wheat in rows, and the barley in the appointed place, and the spelt in the border thereof?" — Isaiah 28:25 (ASV)

When he has levelled its surface. He now speaks about sowing. The sower will not put into the earth as much as he can, nor will he throw it in at random, but will measure the ground, and give to it as much as is necessary; for otherwise the superfluous mass would rot, and not a single grain would take root.

Wheat in measure, and barley measured. He will not mix various seeds, but will allot one part of the field for wheat, another for vetches, and another for cummin. He will do this in measure, for I consider that to be the proper interpretation of שורה (sōrāh). It does not mean excellent or good; for he is speaking about measurement.

Similar statements are made about reaping and threshing, for all kinds of grain are not threshed in the same manner. Wheat is threshed with the wheel of a cart or wagon, vetches with a staff, and cummin with a thicker rod. He speaks according to the custom of the country. This mode of threshing is unknown in any part of France, except Provence. In short, he means that the manner of threshing which is suitable to the grain does not apply equally to all. Besides, the farmer is not constantly or incessantly employed in threshing, but exercises moderation, that he may not bruise the grain.