Today the Gospel reading is one of the most famous in St Matthew's Gospel: the Beatitudes, or 'blessings', which open Jesus' Sermon on the Mount. Faced by having to choose between trying to say something about all the Beatitudes in a small space or focussing on one of them, I am going for the second option.
Happy the pure in heart: they shall see God.
This is surely the most often misunderstood of the Beatitudes. It's not, as so many people think, about sex. Purity of heart means something much more than just sexual purity. It means singleness of heart, integrity.
Devout Jews every day recite the Shema, the verse from the book of Deuteronomy:
You shall love the Lord with all your heart.
And in the psalms we say:
Blessed are those who keep the Lord's testimonies, who seek him with their whole heart.
Looking at somebody lustfully is, yes, a sin against 'purity of heart', but it is so because doing that is failing to give yourself wholly to a person, not giving yourself to a person 'with your whole heart' and also because behaving like that is not serving God 'with your whole heart'.
The good person is the person wholly consecrated to the service of God and to the doing of God's will. As Jesus says later on in the Sermon on the Mount,
Do not lay up for yourselves treasures on earth, but lay up for yourselves treasures in heaven. For where your treasure is, there will your heart be also.
The opposite of a 'pure' heart is a divided heart. As we are told in the letter of St James,
Purify your hearts, you men of double mind.
And how often we are men - and women - 'of double mind' ! Quite a lot of our lives, in fact! Jews of Jesus' time thought that what divides the heart is the evil inclination ... something implanted in us by God and so far good, but when not controlled, something divisive.
It can be very frightening to realise that one bit of yourself is working against the other bit, that your feelings and your ideals, your desires and your beliefs, are pulling in opposite directions ... to realise that (to use the well-known biblical phrase) you are trying to serve God and Mammon. And these days it's more difficult than ever not to end up doing just that very thing.
Jesus says that it's the person with singleness of heart who will see God ... which means that the people who are best prepared to share God's life, to enter heaven, are not necessarily the people we would think - they are not necessarily the people who have busied themselves doing piles and piles of virtuous things, but are very conscious that they have done them, nor the people who have spent their lives metaphorically flicking the dust off their shoulders, the people who've never done anything wrong because they've never taken the risk that's often involved in trying to do something right.
The people who are best prepared to share God's life are, rather, the people who have singleness of heart: who are simple not in the sense of being stupid but in the sense that they are not full of contradictions - who have their priorities right and quietly listen to God.
What the Catholic doctrine of purgatory basically says to us is that, if really deep down we are friends of God, God will share his life with us, but entering God's life means being separated from all in us that's alienfrom God ... and that can be painful, for we often want to cling to those things in us which are unlike God.
The people for whom passing from this life into God's life is not something painful are the people who go to meet God travelling light - not with a whole pile of ungodly clutter.
And those are the people who are 'pure in heart'. Let's pray that we may become people who are 'pure in heart'.