John Gill Commentary Mark 2:23

"And it came to pass, that he was going on the sabbath day through the grainfields; and his disciples began, as they went, to pluck the ears." — Mark 2:23 (ASV)

And it came to pass
The Vulgate Latin adds, "again"; and so Beza says it was read in one of his copies:

that he went through the corn fields on the sabbath day, and his
disciples began, as they went, to pluck the ears of corn ,
and to rub them, and get the grain out of them, and eat them; (See Gill on Matthew 12:1).