We instinctively tend to limit for whom we exert ourselves. We do it for people like us, and for people whom we like. Jesus will have none of that. By depicting a Samaritan helping a Jew, Jesus could not have found a more forceful way to say that anyone at all in need - regardless of race, politics, class, and religion - is your neighbour. Not everyone is your brother or sister in faith, but everyone is your neighbour, and you must love your neighbour.