Psalm 106:19-20. They made a calf in Horeb, and worshiped the molten image. Thus they changed their glory into the similitude of an ox that eateth grass.
There is thought to be an allusion here to a custom which was practiced in Egypt in connection with the worship of the sacred calf, Apis. Godwyn says: “The party that repaired unto him tendered a bottle of hay or grass; which, if he received, then it betokened a good and happy event; if, otherwise, he refused it, then it did portend some evil to come” (Moses and Aaron, book 4, chapter 5).