Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 6:1-5

“Now He says, on the second sabbath after the first, because the Jews called every feast a sabbath. For sabbath means rest. Frequently therefore was there feasting at the preparation, and they called the preparation a sabbath because of the feast, and hence they gave to the principal sabbath the name of the second-first, as being the second in consequence of the festival of the day preceding.”