Mahabharata — Anushasana Parva, Shloka 3
Adhyāya 138: Vāyu’s Exempla on Brāhmaṇa-Prabhāva and a Cosmological Clarification
निरुद्धिग्नस्तु यो दद्यान्मासमेकं गवाह्विकम् | एकभक्तं तथाश्नीयाच्छुयतां तस्य यत् फलम्
niruddhignas tu yo dadyān māsam ekaṁ gavāhvikam | ekabhaktaṁ tathāśnīyāc chruyatāṁ tasya yat phalam |
大自在天说道：“当听那人所得之报：其心不惊不扰，离于忧恼；满一月之中，日日供给母牛应得之食养，而自身一日仅食一次。听此有节之施与克己所结之果。”
महेश्वर उवाच
Educational Q&A
The verse teaches that calm-minded charity (supporting/feeding a cow daily) combined with personal restraint (eating once a day) is a dharmic discipline whose merit yields a specific spiritual reward, to be described in the following lines.
Maheshvara is instructing the listener about a particular vow-like practice: for one month the practitioner provides daily sustenance connected with a cow and maintains an ekabhakta regimen; Maheshvara then invites the audience to hear the resulting ‘fruit’ (karmic/spiritual outcome).