Looking for a reason to accuse Jesus, the scribes and Pharisees were watching Him closely to see if He would heal on the Sabbath.
These two passages of story we had both in Matthew and Mark, and they were there laid together (Mat 12:1; Mar 2:23; Mar 3:1), because, though happening at some distance of time from each other, both were designed to rectify the mistakes of the scribes and Pharisees concerning the sabbath day, on the bodily rest of which they laid greater stress and required greater strictness than the Law-giver intended.
Commenting on Luke 6:1-11
But he knew their thoughts,.... Being the omniscient God; though they had said nothing of their intentions, he knew what they designed, should he heal the man with his withered hand, as they expected he would: and said to the man which had the withered hand, rise up, and stand forth in the midst.
Verse 7. No entry from BARNES for this verse. (f) "heal on the Sabbath day"