Pope Saint Pius’ catechism did not mention common prayer. It stated:
>>15 Q: What else does the First Commandment forbid?
A: The First Commandment also forbids all dealings with the devil, and all association with anti-Christian sect’s.<<
Please don’t twist a saint’s word; it’s not charitable to do so.
Pope Pius X is not the only source of reference, you know.
The re-examination of the Church vis-a-vis the Jewry occurred in the wake of the Second World War and creation of the state of Israel, when it became clear that the Jews have an distinct role in the fabric of the Western Civilization and as a whole do not bear hostility to Christians, whereas often the hostility of the Christians toward the Jews is a gross failure of Christian charity. The Church therefore in her pastoral duty to the Christian world, undertook to ensure that the Jews as a group not be treated as anti-Christian religious community.