vidhi-hīnam asṛiṣhṭānnaṁ mantra-hīnam adakṣhiṇam
śhraddhā-virahitaṁ yajñaṁ tāmasaṁ parichakṣhate||13||

Meaning : Sacrifice that is done without following the rules, without offering food, without chanting mantras, without giving gifts, and without faith that sacrifice is considered tamasic (ignorant).