John Calvin Commentary Luke 6:1

"Now it came to pass on a sabbath, that he was going through the grainfields; and his disciples plucked the ears, and did eat, rubbing them in their hands." — Luke 6:1 (ASV)

On the second-first Sabbath, it is beyond all question that this Sabbath belonged to one of the festival days which the Law required to be observed once every year. Some have thought that there were two festival days in immediate succession; but since the Jews had arranged their festival days after the Babylonian captivity so that one day always intervened between them, that opinion is set aside. Others maintain with greater probability that it was the last day of the solemnity, which was as well attended as the first.

I am more inclined to favor those who understand it as the second festivity in the year; and this agrees exceedingly well with the name given to it, the second-first Sabbath, because, among the great Sabbaths which were annually observed, it was the second in the order of time. Now the first was the Passover, and it is therefore probable that this was the feast of first-fruits (Exodus 23:15–16).