Matsya Purana — The Maheshvara Vow: Śiva-Caturdaśī Vrata
कृत्वा नीलवृषोत्सर्गं श्रुत्युक्तविधिना नरः उमामहेश्वरं हैमं वृषभं च गवा सह //
kṛtvā nīlavṛṣotsargaṃ śrutyuktavidhinā naraḥ umāmaheśvaraṃ haimaṃ vṛṣabhaṃ ca gavā saha //
Having performed the rite of releasing a blue bull according to the procedure taught in the Vedas, a man attains Umā and Maheśvara, along with a golden bull and cows.
This verse does not address pralaya; it focuses on a Vedicly sanctioned donation-rite (nīlavṛṣotsarga) and the spiritual fruit promised from that ritual act.
It frames dāna and properly performed rites as a core householder duty: gifts and releases are to be done strictly by śruti-approved procedure, and such regulated charity is presented as a means to gain religious merit and divine favor.
The ritual significance is explicit: the bull-release must follow śrutyukta-vidhi (Vedic injunction). The verse also implies iconographic/ritual gifting (a ‘golden bull’ and cows) as sanctioned offerings connected with Śiva-Umā devotion.