Matthew 12:9 - Ellicott's Commentary On The Whole Bible

He went into their synagogue — i.e., that of the Pharisees whom He had just reproved, probably, therefore, the synagogue of Capernaum. The narratives in St. Matthew and St. Mark convey the impression that it was on the same Sabbath. St. Luke, however, as if he had made more careful inquiry, states definitely that it was on another, and this the others do not directly contradict.