From: Mark 7:1-13
The Tradition of the Elders
 Now when the Pharisees gathered together to Him (Jesus), with some of the scribes, who had come from Jerusalem,  they saw that some of His disciples ate with hands defiled, that is, unwashed.  (For the Pharisees, and all the Jews, do not eat unless they wash their hands, observing the tradition of the elders;  and when they come from the market place, they do not eat unless they purify themselves; and there are many other traditions which they observe, the washing of cups and pots and vessels of bronze.)  And the Pharisees and the scribes asked Him, "Why do Your disciples not live according to the tradition of the elders, but eat with hands defiled?"  And He said to them, "Well did Isaiah prophesy of you hypocrites, as it is written, `This people honors Me with their lips, but their heart is far from Me;  in vain do they worship Me, teaching as doctrines the precepts of men.'  You leave the commandment of God, and hold fast the tradition of men.  And He said to them, "You have a fine way of rejecting the commandment of God, in order to keep your tradition!  For Moses said, "Honor your father and your mother'; and `He who speaks evil of father or mother, let him surely die';  but you say, `If a man tells his father or his mother, What you would have gained from me is Corban' (that is, given to God)-- then you no longer permit him to do anything for his father or mother,  thus making void the word of God through your tradition which you hand on. And many such things you do."
1-2. Hands were washed not for reasons of hygiene or good manners but because the custom had religious significance: it was a rite of purification. In Exodus 30:17ff the Law of God laid down how priests should wash before offering sacrifice. Jewish tradition had extended this to all Jews before every meal, in an effort to give meals a religious significance, which was reflected in the blessings which marked the start of meals. Ritual purification was a symbol of the moral purity a person should have when approaching God (Psalm 24:3ff; 51:4 and 9); but the Pharisees had focused on the mere external rite. Therefore Jesus restores the genuine meaning of these precepts of the Law, whose purpose is to teach the right way to render homage to God (cf. John 4:24).
3-5. We can see clearly from this text that very many of those to whom St. Mark's Gospel was first addressed were Christians who had been pagans and were unfamiliar with Jewish customs. The Evangelist explains these customs in some detail, to help them realize the significance of the events and teachings reported in the Gospel story.
Similarly, Sacred Scripture needs to be preached and taught in a way which puts it within reach of its hearers. This is why Vatican II teaches that "it is for the bishops suitable to instruct the faithful [...] by giving them translations of the sacred texts which are equipped with necessary and really adequate explanations. Thus the children of the Church can familiarize themselves safely and profitably with the Sacred Scriptures, and become steeped in their spirit" ("Dei Verbum", 25).
11-13. For an explanation of this text cf. note on Mt. 15:5-6. Jesus Christ, who is the authentic interpreter of the Law, because as God He is its author, explains the scope of the fourth commandment and points out the mistakes made by the Jewish casuistry. There were many other occasions when He corrected mistaken interpretations offered by the Jewish teachers: for example, when He recalls that phrase of the Old Testament, "Go and learn what this means, I desire mercy, and not sacrifice" (Hosea 6:6, 1 Samuel 15:22; Sirach 35:4) in Matthew 9:13.
[The note on Matthew 15:5-6 states:
5-6. Over the years teachers of the Law (scribes) and priests of the temple had distorted the true meaning of the fourth commandment. In Jesus' time, they were saying that people who contributed to the temple in cash or in kind were absolved from supporting their parents: it would be sacrilegious for parents to lay claim to this "corban" (offerings for the altar). People educated in this kind of thinking felt that they were keeping the fourth commandment--in fact, fulfilling it in the best way possible--and they were praised for their piety by the religious leaders of the nation. But what in fact it meant was that, under the cloak of piety, they were leaving elderly parents to fend for themselves. Jesus, who is Messiah and God, is the one who can correctly interpret the Law. Here He explains the proper scope of the fourth commandment, exposing the error of Jewish practice at the time.
For Christians, therefore, the fourth commandment includes affectionate help of parents if they are old or needy, even if one has other family, social or religious obligations to attend to. Children should check regularly on whether they are looking after their parents properly.]
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.