POPE BENEDICT XVI yesterday praised the "ecstasy" of physical love between a man and a woman as a pathway leading to the divine love of God. In an encyclical charged with the language of eros, or erotic love, the Pope cautioned against the "debasement" of sexual love as a "commodity to be bought and sold". Quoting the Hebrew Bible's Song of Songs, a book that exalts both the physical and spiritual aspects of conjugal love, he uses the document to reclaim for Christianity the divine potential of the erotic. The Pope concedes that Christianity has been regarded at times as having been opposed to the body, and says that sex is meaningless if not combined with spiritual or divine love. But in Deus Caritas Est (God is Love), his first encyclical since being elected in April, he says that through God, eros can be enobled and purified. The Pope also defends the right of Christian aid agencies to carry out charity work, saying their efforts showed that God and religion can be used for good rather than misused in the name of "vengeance, hatred and violence". Christian aid workers must not proselytise but inspire faith by example. The encyclical is significant because as his first, it sets the tone for his pontificate. Although focusing on love, it is also a sophisticated working-out of the relationship between Church and State, with references to earlier Catholic social teaching. To the surprise of some Vatican insiders, however, it does not address the social and ethical issues that face the Church, and which Pope Benedict handled as guardian of doctrine for the late John Paul II. This week the Pope, 78, told a Vatican conference that he had chosen the theme of love and charity "because the word love is too much abused in the world today". In the encyclical he says: "I wanted at the beginning of my Pontificate to clarify some essential facts concerning the love which God mysteriously and gratuitously offers to man, together with the intrinsic link between that Love and the reality of human love." The first half --- on love --- was written by the Pope in his native German at his summer retreat of Castelgandolfo in the hills south of Rome. The second half, on charity, is a reworking of a draft text which John Paul II --- Benedict's mentor --- did not have time to complete before his death. Vatican sources said the merging of the two halves had proved problematic. Last week the Pope admitted that publication had been delayed by "translation" difficulties. Sources, however said there had been "differences of substance" after the text was passed for re-drafting to papal advisers. Asked at a Vatican press conference whether he had been surprised that a "great theologian" such as Benedict should have involved his advisers so closely Archbishop William Levada, the Pope's American successor as head of the Congregation for the Doctrine of the Faith, replied: "A bit, yes." In the 70-page encyclical, issued in Latin and translated into six languages, the Pope discusses the relationship between eros and agape --- the Greek word for spiritual or higher love. Man, he says, "now considers his body and his sexuality as the purely material part of himself, to be used and exploited at will. Nor does he see it as an arena for the exercise of his freedom, but as a mere object that he attempts, as he pleases, to make both enjoyable and harmless. Here we are actually dealing with a debasement of the human body." Benedict also explores the Church's work in caring for the poor and sick, which he says was as much a part of its mission as spreading the Gospels. But, he argues, Christian charity workers must never proselytise or push an ideology. "Love is free; it is not practised as a way of achieving other ends," he writes. "Those who practise charity in the Church's name will never seek to impose the church's faith upon others. They realise that a pure and generous love is the best witness to God".