The Pharisees criticized Jesus because his disciples picked grain to eat on the sabbath, and Jesus proclaimed himself lord of the sabbath. Following Jesus is more important than following the letter of the law.
Based on Luke 6:1-5:
One sabbath while Jesus was going through the cornfields, his disciples plucked some heads of grain, rubbed them in their hands, and ate them. But some of the Pharisees said, ‘Why are you doing what is not lawful on the sabbath?’ Jesus answered, ‘Have you not read what David did when he and his companions were hungry? He entered the house of God and took and ate the bread of the Presence, which it is not lawful for any but the priests to eat, and gave some to his companions?’ Then he said to them, ‘The Son of Man is lord of the sabbath.’
(New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org)