So, from the standpoint of ethics and human conduct, then, we can say that the ancient brahmanical rules (Vedas, Manu Smṛti, and various sūtras and śāstras) provided a religious justification for social inequality.
These rules upheld the primacy of the caste system, and in doing so they especially cemented the dominance of the Brahmins as the priestly caste that was considered to be the ritually purest caste (or class).