To love our neighbor as ourselves is such a truth for regulating human society, that by that alone one might determine all the cases in social morality.

Locke treats the biblical maxim “love your neighbor as yourself” as more than private piety: he frames it as a rational, society-regulating principle capable of guiding judgments in “social morality.” The claim suggests that moral reasoning about how we treat others can be anchored in a symmetry requirement—extend to others the same concern and respect you naturally claim for yourself. In Locke’s broader moral and political outlook, such a rule supports duties of fairness, restraint, and mutual regard, and it resonates with his view that moral norms can be known and applied through reason to concrete cases in civil life.