Their pure and noble love is a sacred thing. As a priest, I bless it with all my heart. Christian tradition has often seen in Christ's presence at the wedding feast in Cana a proof of the value God places on marriage. "Our Saviour went to the wedding feast," writes St Cyril of Alexandria, "to make holy the origins of human life."

Marriage is a sacrament that makes one flesh of two bodies. Theology expresses this fact in a striking way when it teaches us that the matter of the sacrament is the bodies of husband and wife. Our Lord sanctifies and blesses the mutual love of husband and wife. He foresees, not only a union of souls, but a union of bodies as well. No Christian, whether or not he is called to the married state, has a right to underestimate the value of marriage.

We have been created by God and endowed with an intelligence which is like a spark of the divine intellect. Together with our free will, another gift of God, it allows us to know and to love. And God has also placed in our body the power to generate, which is a participation in his own creative power. He has wanted to use love to bring new human beings into the world and to increase the body of the Church. Thus, sex is not a shameful thing; it is a divine gift, ordained to life, to love, to fruitfulness.

This is the context in which we must see the christian doctrine on sex. Our faith does not ignore anything on this earth that is beautiful, noble and authentically human. It simply teaches us that the rule of our life should not be the selfish pursuit of pleasure, because only sacrifice and self-denial lead to true love. God already loves us; and now he invites us to love him and others with the truthfulness and authenticity with which he loves. It is the paradox expressed in St Matthew's Gospel: "He who seeks to keep his life will lose it; and he who loses his life for my sake will find it."

People who are constantly concerned with themselves, who act above all for their own satisfaction, endanger their eternal salvation and cannot avoid being unhappy even in this life. Only if a person forgets himself and gives himself to God and to others, in marriage as well as in any other aspect of life, can he be happy on this earth, with a happiness that is a preparation for, and a foretaste of, the joy of heaven.

As long as we walk on this earth, suffering will always be the touchstone of love. If we were to describe what occurs in the married state, we could say that there are two sides to the coin. On the one hand, there is the joy of knowing that one is loved, the desire and enthusiasm involved in starting a family and taking care of it, the love of husband and wife, the happiness of seeing the children grow up. On the other hand, there are also sorrows and difficulties — the passing of time that consumes the body and threatens the character with the temptation to bitterness, the seemingly monotonous succession of days that are apparently always the same.

We would have a poor idea of marriage and of human affection if we were to think that love and joy come to an end when faced with such difficulties. It is precisely then that our true sentiments come to the surface. Then the tenderness of a person's gift of himself takes root and shows itself in a true and profound affection that is stronger than death.