Today's readings: Genesis 18, 1-10; Colossians 1, 24-28; Luke 10, 38-42.

The account of the mysterious meeting of Abraham with three men at the Oak of Mamre in the first reading from Genesis has deep significance for our understanding of the way God works in our lives.

We often speak of God's presence as if it is localised, bound to a place and time. But our God is the God who comes, who builds his own sanctuary in our inner selves. As Henri Nouwen writes, "living in the house of God is not only protection against the fearful world, but also a revelation of the inner beauty of God".

God had already made his promises to Abraham. But Abraham was in the dark as to how these promises were to come true. This is also our big issue with God when it comes to the fulfilment of promises. We often experience interior struggles to come to terms with what we expect from God and which seems endlessly so difficult to materialise.

This is the mystery of the three men who in the hottest part of the day appeared to Abraham at the Oak of Mamre, who ate the meal Sarah and Abraham generously offered to them and who announced the unexpected birth of Isaac. The tent of Abraham thus becomes the dwelling place of God. This is how God's revelation occurs.

It is silent prayer, or the patient attitude of listening, we read about in Luke's gospel when Jesus visited Martha and Mary, that slowly melts away our inner restlessness and lifts up our spirit.

Herbert McCabe, a Dominican priest, theologian and philosopher, in a recently published volume on God and Evil, the sixth which appeared since his death in 2001, writes that "When we speak of God, we do not clear up a puzzle, we draw attention to a mystery."

Paul, in the second reading from Colossians, speaks of this 'drawing attention to a mystery' when he refers to his suffering and explains it as a sort of "making up all that has still to be undergone by Christ for the sake of his body, the Church".

The mystery, he continues, is Christ among you, that mystery which is still unfolding but which can easily remain hidden as in the case of Martha in Luke's account who, though physically in the presence of Jesus, totally missed meeting with him because she worried too much.

What is it that closes our minds and eyes to this mystery? What is it that discloses it? Jesus tells Martha that Mary had chosen "the better part and it is not to be taken from her". Hospitality, where God is concerned, is not just about providing a service, but about receiving a gift.

This is basically what the two stories of hospitality in Genesis and in Luke's gospel show. Abraham's hospitality is immediately ex-changed. His gentle invitation opened the way for a radical turning point in his life. "I shall visit you again next year without fail, and your wife will then have a son".

Same with Luke's text which, through Mary and Martha, depicts the Church's present-day malaise, a Church very much taken up by activism, and a Church which has so much difficulty with listening attentively to God's revealing spirit and to the real feelings and needs of people. As the Old Testament scholar Walter Brueggemann writes in his book The Prophetic Imagination, "The task of prophetic ministry is to nurture, nourish and evoke a consciousness and perception alternative to the consciousness and perception of the dominant culture around us."

Today's readings illustrate a basic principle in the building up of truly Christian communities: it is the preaching of the Word and listening to it that give birth to discipleship, which is what we mostly need today.

This is the radical choice the Church is faced with in our days: to set right its priorities and remain focused, lest it misses completely what it was meant to exist for, namely to make disciples of Jesus.