Matsya Purana — Characteristics of Dvāpara and Kali Yugas
नाधीयते तथा वेदान् न यजन्ते द्विजातयः उत्सीदन्ति तथा चैव वैश्यैः सार्धं तु क्षत्रियाः //
nādhīyate tathā vedān na yajante dvijātayaḥ utsīdanti tathā caiva vaiśyaiḥ sārdhaṃ tu kṣatriyāḥ //
The twice-born no longer study the Vedas, nor do they perform sacrifices; and the Kṣatriyas too decline, along with the Vaiśyas.
This verse is not about cosmic pralaya; it describes a moral and social decline (dharma-kṣaya) where Vedic study and yajña fade, leading to the weakening of the social order.
It warns that when the twice-born abandon Vedic learning and sacrifice, the Kṣatriya’s stabilizing role also deteriorates. For kings, it implies protecting dharma by supporting education, rites, and proper livelihood; for householders, it stresses maintaining svādhyāya (study) and yajña as pillars of social health.
The ritual point is central: the cessation of yajña (sacrificial worship) is presented as a key symptom of decline. No specific Vāstu or temple-architecture rule is stated in this verse, but it indirectly underscores the broader Purāṇic emphasis on sustaining ritual institutions.