2 They noticed that some of his disciples weren't being careful with ritual washings before meals. 3 The Pharisees - Jews in general, in fact - would never eat a meal without going through the motions of a ritual hand-washing, 4 with an especially vigorous scrubbing if they had just come from the market (to say nothing of the scourings they'd give jugs and pots and pans).
Matthew Henry's Commentary on Mark 7:2-4
Commentary on Mark 7:1-13
(Read Mark 7:1-13)
One great design of Christ's coming was, to set aside the ceremonial law; and to make way for this, he rejects the ceremonies men added to the law of God's making. Those clean hands and that pure heart which Christ bestows on his disciples, and requires of them, are very different from the outward and superstitious forms of Pharisees of every age. Jesus reproves them for rejecting the commandment of God. It is clear that it is the duty of children, if their parents are poor, to relieve them as far as they are able; and if children deserve to die that curse their parents, much more those that starve them. But if a man conformed to the traditions of the Pharisees, they found a device to free him from the claim of this duty.