Superficially there are many types of Judaism and Christianity, often overlapping. For example, there are professedly religious Jews who defy Sabbath and the Christians who observe it. Reformist Judaism follows much of the practices of protestant Christianity. The issue of Jesus’ resurrection is practically insignificant. Suppose for a moment that Jews accepted the resurrection as a historical fact. What next? How does that change our life? Shall we abandon the commandments? No. Jesus told the crowd to do as the Pharisees teach, and that included the Oral Law codified in Talmud. Shall we follow an arbitrary apostolic set of rules? But James only commanded to abstain from blood; he told nothing about murder or stealing. Shall we assume those are not prohibited in Christianity? Shall the rule of positive reciprocity direct us? But how? Good Christians killed good Jews out of love for the fellow Christians. Love everyone is too vague to be practiced. Israel does not live with the Basic Law only, nor does America with the Bill of Rights. People need more detailed instructions. In Judaism, those are the commandments. Small communities of early Christians could abandon the law; their members were close and could love each other, even though Paul’s letters picture discontent communities. After Christianity has expanded, its legists arbitrarily reintroduced some commandments. Christians reject at least one of the Ten Commandments, the Sabbath, but accept the second-tier commandments such as prohibitions on usury and homosexuality.

The real difference between the two religions is practicality. Judaism is practical while Christianity – idealistic. Social teaching of Judaism is based on negative reciprocity, Do not do unto your neighbor what is hateful to you. Christianity enhanced that rule just a bit, and made it impractical. Positive reciprocity, Treat your neighbor as yourself, especially when neighbor means everyone, is unworkable. We cannot feed everyone before sitting down at our meal, nor could we help everyone in dire need before buying non-essential goods for ourselves. Idealism sounds great, but it is not. People who cannot practice rules abandon them. They need to rationalize the failure. The rule of positive reciprocity cannot be imagined wrong, and so they find wrong with it’s the rule’s objects. People not loved become demonized: look, even good Christians are unable to love them. Hatred to aliens is another side of the universal love. Christians cannot love the Jews who reject their teaching; many, therefore, hate the Jews.

Christian idealism caused the Jews many problems. Leftist political idealism of love and good faith settlement with enemies does likewise.