This Sunday's Liturgy offers us a fundamental teaching: the need to pray always, without tiring. At times we grow weary of praying, we have the impression that prayer is not so useful for life, that it is not very effective. We are therefore tempted to throw ourselves into activity, to use all the human means for attaining our goals and we do not turn to God. Jesus himself says that it is necessary to pray always, and does so in a specific parable (cf. Lk 18: 1-8).
This parable speaks to us of a judge who does not fear God and is no respecter of persons: a judge without a positive outlook, who only seeks his own interests. He neither fears God's judgement nor respects his neighbour. The other figure is a widow, a person in a situation of weakness. In the Bible, the widow and the orphan are the neediest categories, because they are defenceless and without means. The widow goes to the judge and asks him for justice. Her possibilities of being heard are almost none, because the judge despises her and she can bring no pressure to bear on him. She cannot even appeal to religious principles because the judge does not fear God. Therefore this widow seems without any recourse. But she insists, she asks tirelessly, importuning him, and in the end she succeeds in obtaining a result from the judge. At this point Jesus makes a reflection, using the argument a fortiori: if a dishonest judge ends by letting himself be convinced by a widow's plea, how much more will God, who is good, answer those who pray to him. God in fact is generosity in person, he is merciful and is therefore always disposed to listen to prayers. Therefore we must never despair but always persist in prayer.
The conclusion of the Gospel passage speaks of faith: "When the Son of Man comes, will he find faith on earth?" (Lk 18: 8). It is a question that intends to elicit an increase of faith on our part. Indeed it is clear that prayer must be an expression of faith, otherwise it is not true prayer. If one does not believe in God's goodness, one cannot pray in a truly appropriate manner.
Faith is essential as the basis of a prayerful attitude.
[Pope Benedict, homily for the canonisation of the blessed, 17 October 2010]