He appears to have become more hostile to Jews in his later life, and this can be traced through his theological investigations. Earlier in his life, while lecturing in Oxford, he analysed the Psalms and Paul's Letter to the Galatians. He concluded that the Jews are wedded to the past and their lineage, rather than a search for salvation, following the work of Chrysostom. In his analysis of Galatians and De cessatione legalium, citing Jerome he sets out his understanding of the status of the Old Law, and concludes that it had been "made void" by the resurrection of Christ, and that the Jewish faith was therefore heretical and blasphemous. He followed the view of Augustine and Innocent III, who had reiterated these in recent Papal Bulls that the Jews were guilty for death of Christ, but just as Cain, who had killed Abel, was allowed to live as punishment, so Jews were to live in exile and servitude as punishment for their sin. Jews were not to be allowed to live in luxury from the proceeds of usury, and any Christian ruler allowing or the "oppression" of Christians through usury would be share the Jews' punishment in the next life. Nevertheless, as Bishop, he seems to have taken few practical actions against Jews, in contrast, for example to his associate Walter de Cantilupe. One concrete example can be found in the mid 1240s, where in a letter to his archdeacons, he warns them among many other matters, that they were ensure that Christians and Jews do not associate.