Augustine of Hippo — as excerpted in the Catena Aurea on Mark 2:23-28

“(de Op. Monach. 23) For it was a precept in Israel, delivered by a written law, that no one should detain a thief found in his fields, unless he tried to take something away with him. For the man, who had touched nothing else but what he had eaten, they were commanded to allow to go away free and unpunished. Wherefore the Jews accused our Lord’s disciples, who were plucking the ears of corn, of breaking the sabbath, rather than of theft.”