In the Greek and Roman world, Ehrman argues there isn’t a universal neighbor ethics like a Greek should love every other Greek. This is on the other hand present in the Old Testament with every Israelite should love every other Israelite, stranger or not. Jesus radicalizes this teaching, such as with the parable of the good Samaritan, to care for one’s enemy as more important than herself, and so is a mandate to care for all people: agape (altruism) whether you like the person or not.