The obligation to honor parents is close to universal across ethical traditions, but the weight and structure given to it in Confucian thought is distinctive enough that comparison with two other classical formulations, biblical and Aristotelian, clarifies what makes xiao unusual.
The fifth of the Ten Commandments, "honor your father and your mother" (Exodus 20:12), is stated as one obligation among ten others of comparable rank, addressed to the same worshipping community as commandments concerning God, the Sabbath and one's neighbor, and biblical and later Jewish and Christian ethical reflection, while treating filial honor as serious and grounding real legal consequences in biblical law, never elevates it to the position of a root or foundation from which the rest of ethics grows outward, as the Analects explicitly do. Aristotle, in the Nicomachean Ethics, treats the obligation owed to parents as a species of friendship based on unequal standing, owed because parents are a kind of cause of one's existence and cannot be adequately repaid, but Aristotelian ethics grounds the good life ultimately in the individual's own rational flourishing (eudaimonia) rather than, as Confucian thought does, treating relational duty itself as constitutive of what a good life consists in.
What is distinctively Confucian is the systematic claim, developed at length in the Classic of Filial Piety and defended by the tradition's harshest modern critics as much as its defenders, that filial piety is not one virtue alongside others but the generative root from which every other social and political virtue is said to grow, a claim considerably stronger than the comparable, more modest place parental honor occupies in either the biblical or the Aristotelian scheme.