Mundaka 2.03

यस्याग्निहोत्रमदर्शपूर्णमासमनाग्रयणमतिथिवर्जितं च। अहुतमवैश्वदेवमविधिना हुत मासप्तमांस्तस्य लोकान् हिनस्ति ॥३॥

yasyāgnihotramadarśapūrṇamāsamanāgrayaṇamatithivarjitaṃ ca। ahutamavaiśvadevamavidhinā huta māsaptamāṃstasya lokān hinasti ॥3॥

[यस्य (yasya) - whose; अग्निहोत्रम् (agnihotram) - Agnihotra; अदर्श (adarśa) - new moon; पूर्णमासम् (pūrṇamāsam) - full moon; अनाग्रयणम् (anāgrayaṇam) - without first fruits; अतिथिवर्जितं (atithivarjitaṃ) - without guest; च (ca) - and; अहुतम् (ahutam) - unoffered; अवैश्वदेवम् (avaiśvadevam) - without Vaiśvadeva; अविधिना (avidhinā) - without proper method; हुतम् (hutam) - offered; मासप्तमान् (māsaptamān) - seven months; तस्य (tasya) - his; लोकान् (lokān) - worlds; हिनस्ति (hinasti) - destroys;]

The one who performs Agnihotra without observing the new moon and full moon rituals, without offering the first fruits, without hosting guests, without the Vaiśvadeva offering, or is performed improperly, destroys his worlds for seven months.