Here Jesus teaches the priority of the law of mercy over the Sabbath. What is interesting is that the teachers of the law often debated about which law might take precedence when two came into conflict. For example, what if a circumcision (to be done on the 8th day) fell on the Sabbath? Jesus uses the example of David eating the sacred bread to show that showing mercy is a priority in the law, even on the Sabbath! He challenges the religious leaders about the man with a withered hand by asking: “Is it lawful to do good on the Sabbath or do do evil?” By his actions and teaching Jesus shows that mercy and love should rule the Sabbath, and in truth should rule the law:
Romans 13:10 “Love does no wrong to a neighbor. Therefore love is the fulfillment of the law.”
Unfortunately that understanding, along with the revelation that He is the “Lord of the Sabbath,” is enough to cause them to be angry and debate what they should do about Him. However His example and teaching are enough to draw others to Him, and He chooses 12 to be especially close to Him. Notice that He did it after prayer, and that He included a traitor in the midst. He went with God’s plan first and foremost in His life, and thereby shows us the way we should be.