Matthew Henry Commentary Luke 6:1-5

"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. But certain of the Pharisees said, Why do ye that which it is not lawful to do on the sabbath day? And Jesus answering them said, Have ye not read even this, what David did, when he was hungry, he, and they that were with him; how he entered into the house of God, and took and ate the showbread, and gave also to them that were with him; which it is not lawful to eat save for the priests alone? And he said unto them, The Son of man is lord of the sabbath." — Luke 6:1-5 (ASV)

Christ justifies His disciples in a work of necessity for themselves on the Sabbath day, which was plucking ears of corn when they were hungry. But we must take care that we do not mistake this liberty for a license to sin. Christ wants us to know and remember that it is His day, which is therefore to be spent in His service and for His honor.