Charles Spurgeon Commentary Mark 2:25-28

"And he said unto them, Did ye never read what David did, when he had need, and was hungry, he, and they that were with him? How he entered into the house of God when Abiathar was high priest, and ate the showbread, which it is not lawful to eat save for the priests, and gave also to them that were with him? And he said unto them, The sabbath was made for man, and not man for the sabbath: so that the Son of man is lord even of the sabbath." — Mark 2:25-28 (ASV)

He has made it no longer a day of bondage, but a day of blessed rest and holy service for God. Works of necessity, works of piety, and works of mercy, are not only permitted, but are also commanded on the Sabbath day.