The Catholic Theological Association of Great Britain had a rather truncated and concentrated annual conference in Leuven in September 2007. In order to mesh with the theme of the conference of the European Society for Catholic Theology that was held in the days following with its interest in religions and world-views in present-day Europe, the CTA decided to examine the bases for discussion between Christianity and the other two major monotheistic religions that trace their origins back to Abraham. Hence the title “Children of Abraham”. This is not only a serious issue but a seriously big topic and the five papers presented at the conference could only raise issues – opportunities and difficulties – to be faced in entering into such a dialogue. All the papers come from the Christian side and so do not represent that dialogue itself. They are a propaedeutic to dialogue.

Of course, Christianity finds itself in an odd position in the middle in this dialogue with Judaism and Islam. Christianity claims to share a historical tradition with Judaism up to the time of Jesus but then says that a new form of revelation arrived within the Abrahamic tradition to take that tradition to a new stage of development, while Judaism says this is an alien intrusion that must be set aside. Islam in the seventh-century CE then says the same about their prophet Muhammad – a new revelation has come – and while Judaism has a consistent tactic in rejecting these two ‘new revelations’, Christianity has to change its tactic. Christianity imposes newness on Jewish religion but spurns the newness of Islam. The Church perhaps supersedes Judaism but rejects the supersession of Islam. This tactic requires some astute theological footwork from Christianity that is not obviously called for in Judaism or Islam where they can adopt a consistent though opposite strategy.

Supersession, however, is a problematic word in Christian-Jewish dialogue because it has the sense not only of bringing something new which Christians claim surpasses the old, but also the additional sense of annulling and usurping what has gone before. Because of this the papers here avoid the language of supersession in order to support the continuing validity and value of Judaism. Indeed if Christianity were to maintain the language of supersession, there would be no dialogue.

In this context it is instructive to read the surviving letters of that first-century Christian (i.e. messianic) Jew, Paul. He was not himself a supersessionist who believed that Jewish religion no longer had value or purpose, but he certainly believed that all Jews (and a fortiori all people) should believe what he believed about Jesus. He was no relativist who believed that either tradition would do. Paul believed that Christianity (as it came to be called) surpassed Judaism but in English we do not seem to have a word that stands between ‘supersede’, with its sense of abrogating what has gone before, and ‘relative’, with its sense that all traditions are equally good and true, and differ only culturally and historically. Perhaps ‘succeed’ would do. Christianity emerged from Jewish religion and followed on – succeeded – historically, but Pauline Christianity also believes that through Christ it has succeeded where the temple and synagogue had failed to unite all nations in the worship of the God of Abraham, Isaac and Jacob. Maybe Christians can claim to be “successionists”; it is not a word that Jews will like but they should not find it insulting.

In this regard Paul at the outset laid down a benchmark for Christian thinking but he also remains a problem. The key texts in Paul are Galatians 3–4, Romans 4 and 9–11 and in Galatians he looks suspiciously like a supersessionist. First, however, we should avoid anachronism. There is no evidence from Paul's letters that there was a religion called Christianity before Nero's persecution (and Paul did not write any letters after that!). For Paul, whatever conflict there was was within Jewish religion – should one even speak of ‘Judaism’ before the reconstitution of Jewish religion after the fall of Jerusalem around the Book, in the absence of temple, sacrifices and priests, and without even a so-called “promised land” from the middle of the second century to the middle of the twentieth?

In his allegory of two covenants in Galatians 4.21–26, Paul delineates two covenant traditions related to Abraham's sons: Ishmael and Isaac. Ishmael is the child of the slave woman Hagar; he is a slave born according to the flesh; his mother is from Mount Sinai “bearing children for slavery”; this mountain is in Arabia, he tells us, and corresponds to the present Jerusalem. Paul's exegesis would not pass muster in an undergraduate class but that is his position: non-messianic Jews are descended from Abraham through Hagar and Ishmael. On the other side there is Isaac, the child of the free woman Sarah, born through the promise [of God to Abraham]; his mother corresponds to the Jerusalem above, in the heavens; she is free and she is our mother. So messianic Jews, who came to be called Christians, are children of Abraham via Sarah and Isaac. Both Jews and Muslims ought to find Paul's genealogy surprising and shocking.

We know that Paul did not think that Christ-believing gentiles should be required to keep all the demands of the Mosaic law and in this he had the backing of an apostolic council, but did he think that Christ-believing Jews could continue to keep the whole Law if they found it culturally attractive, rather like present-day Catholics preserving the Tridentine rite of the mass? Consider what Paul writes at the end of Galatians 4.

Paul is quite unequivocal about non-messianic Jewish religion, even though historical context has added an edge to his language in his struggle against Judaising Christians in Galatia. Ask yourself: would Paul have circumcised his son? I don't think so. In Galatians the Law is slavery.

Is Paul less of a supersessionist in Romans? His language about the Law is much more temperate in this letter where he regards Torah as a gift from God, and here he is more generous to the religion of his forbears: “to them belong the adoption, the glory, the covenants, the giving of the law, the worship and the promises; to them belong the patriarchs, and from them, according to the flesh, comes the messiah” (9.4f.). Not a supersessionist here, then. But his anguish for his own non-Christ-believing people is precisely because of their refusal to believe what Paul takes to be the fulfilment of God's promises in Christ. He describes his own Christ-believing ekklesia, those who he calls “the saints”, as a faithful remnant (11.5) and Paul draws a parallel with earlier periods of Israelite history when a majority of Jews had proved to be faithless and had to be corrected, for example at the time of Elijah (11.2) and Isaiah (9.27). So a remnant will be saved, but does that mean God has rejected his people? Or that they have stumbled so as to fall? By no means (11.1, 11). This then leads to Paul's image of the olive tree which has been pruned and grafted (11.17–24) and his vision that in the end “all Israel will be saved” (11.26). But it is a vision that first requires “the full number of the Gentiles” to come in!

In Romans, then, Paul regards Abraham as the father of all Jews, even those who do not (yet) believe in Christ, and of all those gentiles who have come to believe that Christ is the fulfilment of God's promises. In 9.6ff. he repeats his idea from Galatians that not all Abraham's children are true descendents but this clashes with his idea of a faithful remnant and the eventual return of faithless Israelites. Much water has passed under the religious bridge since the time of Paul and his argument about descent that occurs in Galatians – not so much an argument as a statement – must be abandoned for any present-day dialogue to be fruitful. And the argument about descent clashes or at least does not fit easily with the line taken in Romans. Jews are clearly true descendents of Abraham and not just “according to the flesh”. The idea of remnant better represents the Christian position and has a scriptural pedigree. (It is not clear whether the remnant of Romans 11 refers to all Christian believers or specifically to Jewish Christians; many commentators opt for the latter but the point is not important here.) In dialogue with Jews, Christians may claim to have ‘succeeded’ Judaism but they will have to distance themselves from the unreality of Paul's vision of an end-time when all gentiles have been saved and God finally chooses to graft the faithless Israelites back in. It expresses Paul's trust in the righteousness of God but is hardly to be taken literally as a historical programme.

Paul's ideas, then, can be subjected to criticism but he is central to any dialogue. He presents difficulties for both sides but he cannot be ignored. Much as he values his ancestral religion and experiences “great sorrow and unceasing anguish” on behalf of his own people, he certainly thought that God had done something new and necessary in Christ, and it is something that the synagogue rejects. For the synagogue, Paul's religion is at best a Jewish heresy and at its worst an idolatry, which was the response of Moses Maimonides, so John McDade tells us.

McDade recognises the stumbling blocks of dialogue from his own experience, but in the opening paper here he is more concerned with commonalities and how a Christian theology of Judaism might look. His key idea is that Christianity is a reconfigured Judaism and the church a reconfigured Israel. Not an opponent or a replacement; a reconfiguration of Israel that does not abrogate the synagogue. He resists the idea that the church is a purely gentile phenomenon. There is a sense in which the church is always a part of Israel (though not a sense that the synagogue recognises) but reshaped since the coming of Christ. The wisdom of God comes to Christians through Christ, he says, just as that wisdom came to Jews and continues to come to Jews through Torah. The difficulty then is understanding how Torah might relate to Christ. Paul thought he knew but it's not so evident to New Testament scholars who continue to dispute their reading of Paul on the status of the Law. What we can agree, from a Christian perspective, is that Christ's mission to Israel and to the nations is unfinished but, more controversially, Father McDade thinks that the church can play no active role in Christ's mission to Israel. One wonders: is this for historical or theological reasons, or both? And is there then no human agency that can promote Christ's mission to Israel?

Mary Mills acknowledges Paul's classic interpretation at the beginning of her paper on Abraham and the women in his life but announces that she will not follow Paul's symbolic interpretation of Genesis. She carries out an alternative exploration of Genesis 12–24 by using recent narrative theology to see where it takes us. She enters imaginatively into the stories and engages with the characters of these chapters to discover possible models of human identity, particularly the idea of motherhood and how Sarah pulls all the strings in Abraham's domestic drama of marriage, birth and descent.

Living and working in the Tantur Community in Jerusalem has informed David Burrell's practice of dialogue, he tells us, and his paper offers us a bridge from Christianity's engagement with Judaism to her conversation with Islam. His paper deals with the intellectual humility required in any dialogue and also with some of the obstacles that face us at the present time. He looks back to the classic moment in the Middle Ages when all three traditions could engage with problems about faith and reason through a common engagement with “a pervasive philosophical tradition – Aristotle in a neo-Platonic key” which encouraged the traditions to learn from each other. Professor Burrell regrets the absence of a similar overarching framework now. Equally problematic is the logic of faith whereby each religion makes claims to truth which implies that competing claims must be wrong. To deal with this he recommends the strategy of Thomas Aquinas when facing apparent contradictions between faith and reason. As both come from God the creator, there can be no contradiction. The fault must be in our formulation or in our argumentation. So in a different context, Burrell asks, “how can we extend it [Aquinas's principle] … to conflicts between formulations of different faiths in one God, when those formulations appear to be outright contradictory?” He suggests moves that “should motivate us to attempt to reconcile apparent contradictions between Abrahamic faiths in a manner similar to the way philosophical theologians of these traditions had proceeded to reconcile their respective revelations with reason”. Like McDade, he wants to build on commonalities in a practice of dialogue that will lead from intellectual humility to respect, empathy, mutual hospitality and friendship.

Chris Hewer believes that as a Christian he is required to take God seriously and also “to take seriously the message and lived faith of God's Muslim children”. This presents the very serious challenge to consider “what God might be saying to me as a Christian in and through the Qur'an, Muhammad and lived out faith of Muslims”. At the same time he is hard-headed about the theological difficulties in conversing with Muslims. The Qur'an makes statements about Jesus that Christians could never accept – if they did accept them they would effectively become Muslim – and insists that it is Christians who have distorted what Jesus was about. The blame is placed primarily with Paul (again). As the status of the Qur'an in Islam is non-negotiable, the scope for progress in a Christian-Muslim dialogue is limited. But there is room for removing mutual misunderstandings, for developing a methodology that goes beyond polemics and apologetics, that recognises the limitations of any religious understanding and that “returns the academic theological discourse to the realm of faith and accountability before God”.

After the broad theological statement about Islam from a Christian perspective by Chris Hewer, we are offered a more particular and detailed look at a couple of Muslim writers by Simonetta Calderini. She attempts to move us away from a homogeneous and monolithic view of Islam – all too easy for an outside observer – to suggest that there is more variety than we might realise by looking at two ‘alternative voices’. Amina Wadud is an American convert to Islam who has incorporated feminist perspectives into Islam and has brought with her an awareness that there are other religions than Islam that cannot and should not be lightly dismissed. Wadud is a controversial and perhaps peripheral figure but certainly not a dissident one. More representative of legitimate but uncommon Islamic theology is Hasan Askari, an Indian who accepts the historical legitimacy of Christianity and Judaism, even though they have been surpassed, but who looks forward to a ‘spiritual quest’ that transcends all historical religions. Askari accepts a multiplicity of forms of religion without relativising the truth-claims of Islam but how far Askari represents a door through which Christians, Jews and Muslims can proceed together remains to be seen. It is a door that Orthodox Jews may not want to take, that Christians would approach with caution, and that most Muslims at the moment would want to slam shut. But some would take it if the invitations were sent out.