מדרש על ירמיהו 28:13

An analogy: A man had a calf, which he groomed, curried, and fed vetch — to groom him for plowing! When the calf was grown, his master placed the yoke upon it — at which it bolted, broke the yoke, and snapped its ends, viz. (Jeremiah 28:13) "You broke yokes of wood, etc."