Then Pharisees and scribes came to Jesus from Jerusalem and said, “Why do your disciples break the tradition of the elders? For they do not wash their hands when they eat.” He answered them, “And why do you break the commandment of God for the sake of your tradition? For God commanded, ‘Honor your father and your mother,’ and, ‘Whoever reviles father or mother must surely die.’ But you say, ‘If anyone tells his father or his mother, “What you would have gained from me is given to God,” he need not honor his father.’ So for the sake of your tradition you have made void the word of God. You hypocrites! Well did Isaiah prophesy of you, when he said: “‘This people honors me with their lips, but their heart is far from me; in vain do they worship me, teaching as doctrines the commandments of men.’”
In this passage, Jesus is sought out by religious leaders and challenged--they are beginning to truly see Him as a threat. The leaders point out that it has long been a tradition of the elders to wash their hands when they eat. Now this is not a part of the Levitical code, but it was an extra sign of purity--they feared allowing dust or something impure to sully their food, and thus get into their bodies and limit their purity.
When Jesus responds back, He is not saying that He is anti-hand-washing! (Sorry kids, you'll still have to wash your hands before dinner, as mom commands.) Instead, He scoffs at their adding of traditions upon laws.
Notice that Jesus never really answers their question here. He is not concerned with any specific tradition at all; instead, He attacks their traditions en masse. He takes a more abstract approach, pointing out that the Jews have added so many traditions that they even break the laws that the traditions were originally built upon!
As an example, Jesus quotes what appears to be a common practice. Jesus sites the Old Testament, where God tells the Israelites to honor and care for their parents. Then Jesus refers to a common practice of the day: if you choose to do so, you can give the money and time and talent which would have gone to honoring your parents and instead give that to God.
First, let us not fail to notice the self-serving nature of this tradition. Here we have religious leaders telling people that they can ignore the requirements of the Scriptures and instead of honoring their parents, give honor and money to God. How will they give that money and honor to God? Why, through His temple and synagogues, of course. And who benefits financially from this arrangement? Not coincidentally, it is the religious leaders who benefit.
Second, note that Jesus here is saying something that very few Christian pastors today would say! He is saying, "Take care of your earthly family first, and THEN worry about God's house and church." Jesus is showing the same priorities here that He shows throughout the rest of Scripture: first comes obeying God, then comes taking care of others (including family), and only then comes taking care of the church. This was quite a departure from the Pharisees, who saw "loving God" and "taking care of the church" as the same thing, and thus loving others could take a back seat. But no, as He always did, Jesus put relationships before religion--first relationship with God, then relationship with others.
So Jesus angrily calls them hypocrites, saying that their practice of allowing their parents to suffer and starve while keeping their tithes and offerings flowing into the church is wrong. This tradition, He says, actually deliberatly violates the laws of God. He then chastises them with a verse from Isaiah, reminding His listeners that Israel has been putting traditions before God's law for generations--all the way back to Isaiah.
Jesus goes so far as to say that if one is teaching traditions of men, then they worship Him "in vain"! He warns very clearly that commandments of men must not be taught as doctrines.
Oh, but how often do we see this in the church? How often do we hear pastors teach that the Levitical tithe (10%) is a modern law, and we should give offerings above and beyond it, and we must be wary to ensure that our tithe is off the gross rather than the net? How often do we teach that Young Earth Creationism is the one and only way to understand Genesis 1? How often do we teach that certain clothing should be worn on Sunday morning, or that a church is not a good church unless they do this program or that one? How often do we teach that churches should have (or abstain from) real wine in service, or how often the Lord's Supper must be celebrated, or that worship must have such-and-such instruments or a specific order?
Do you see that we, too, are in danger of teaching our traditions as doctrine? That we, too, run the risk of breaking God's true commandments because we are so focused upon our own tradition? This is something which I call the "Law-Grace-Law" cycle: that we are freed from the Law, and so we hurry about building our own new law to replace it. Ironically, you even see this among some very strong Christians who, in their attempt to distance themselves from emerging churches and Evangelicalism, end up making following "old traditions" (certain Bibles, creedal nature of church, etc.) as a superior version of faith.
Jesus, in this passage, never actually answers the question asked to Him. He doesn't say why His disciples eat without washing their hands. But instead, He calls to task those who pay attention to, and judge others based upon, man-made traditions. Such things are of no relevance, He argues. What matters is a man's relationship to God, and his treatment and love of his fellow men; this is all that matters. And, Jesus says, when we let our traditions get in the way of those two factors, then we find ourselves breaking God's laws.