He who eats without having performed the rites in honour of the celestials or those in honour of the departed Manes or without having offered (even) oblations of water to both the Rishis and the departed Manes has to take birth as a crow.
देवकार्यमकृत्वा तु पितृकार्यमथापि वा। अनिर्वाप्य समश्चन् वै मृतो जायति वायसः॥