How do we know God’s Law and follow it?  God created human beings to know him, to love him and to serve him in this world and to be happy with him for ever in the next.  This means that our human nature is orientated towards God and that some basic values follow from this, e.g. respect for life.  It is possible for all human beings to come to some appreciation of these basic laws simply by reflecting on human nature.  However, left to our own devices we can get things wrong and this is why God gave Moses a more specific set of rules to live by, the Ten Commandments.  Because they are revealed by God they apply to every human being, even if lack of awareness provides an excuse.  Applying these in the concrete situations of everyday life is often difficult and so human teachers try to provide more detailed guidance.  The rabbis described these as ‘setting a hedge about the Law’ so that people would not come close to breaking it.  The danger is that these can take over and we can lose sight of the basic principles they are intended to protect.  In today’s Gospel Jesus finds fault with the scribes and Pharisees for focussing on external purity but ignoring purity of heart.  We need to avoid the two extremes of ticking boxes with our conduct and giving so much weight to our good intentions that putting them into practice seems of minor importance.  Integrity of life calls for both good intentions and good actions.