BG 17.13
विधिहीनमसृष्टान्नं मन्त्रहीनमदक्षिणम्।श्रद्धाविरहितं यज्ञं तामसं परिचक्षते।।17.13।।
vidhi-hīnam asṛiṣhṭānnaṁ mantra-hīnam adakṣhiṇam śhraddhā-virahitaṁ yajñaṁ tāmasaṁ parichakṣhate
vidhi-hīnam—without scriptural direction; asṛiṣhṭa-annam—without distribution of prasādam; mantra-hīnam—with no chanting of the Vedic hymns; adakṣhiṇam—with no remunerations to the priests; śhraddhā—faith; virahitam—without; yajñam—sacrifice; tāmasam—in the mode of ignorance; parichakṣhate—is to be considered
Translation
They declare that sacrifice to be Tamasic which is contrary to the ordinances of the scriptures, in which no food is distributed, and which is devoid of mantras, gifts, and faith.
Commentary
17.13 विधिहीनम् without keeping to ordinance? असृष्टान्नम् in which no food is distributed? मन्त्रहीनम् which is devoid of Mantras? अदक्षिणम् which is devoid of gifts? श्रद्धाविरहितम् which is devoid of faith? यज्ञम् sacrifice? तामसम् Tamasic? परिचक्षते (they) declare.Commentary A sacrifice performed by a Tamasic man is never guided by any consideration for the prescribed rites or incantation. You
will find every irregularity in this sacrifice. No food is distributed. No fees which are prescribed in the scriptures are given to the priests. The Mantras are not changed properly. The hymns recited are defective in utterance and accent. Sometimes there is no recitation at all. There is no faith. A man who performs such a sacrifice does not get any merit.