Bhagavad Gita Chapter 17 Verse 13 भगवद् गीता अध्याय 17 श्लोक 13 विधिहीनमसृष्टान्नं मन्त्रहीनमदक्षिणम्। श्रद्धाविरहितं यज्ञं तामसं परिचक्षते।।17.13।। हिंदी अनुवाद - स्वामी तेजोमयानंद ।।17.13।। शास्त्रविधि से रहित? अन्नदान से रहित? बिना मन्त्रों? बिना दक्षिणा और बिना श्रद्धा के किये हुए यज्ञ को तामस यज्ञ कहते हैं।। Kumara Vaishnava Sampradaya - Commentary Any religious ritual or ceremony of any kind that is vidhi-hinam or devoid of following the ordinances and injunctions of the Vedic scriptures and without being conducted by Vaisnavas and brahmanas who are pre-eminent both in precept and in practice is recognizably known to be fully situated in tama guna the mode of ignorance. The words asrsta-annam means without the sanctified food and ingredients required to perform a bonafide yagna or propitiation and worship. The prohibition is that no ingredient may be acquired from those without faith in Lord Krishna; so it is a mandatory requirement that all ingredients are to be received only from devotees. Those situated in tama guna cannot fulfil this mandate. So in conclusion whatever religious activity that is performed without adhering to the authority of the Vedic scriptures, without Vaisnavas and brahmanas chanting Vedic mantras and without adoration of the Supreme Lord Krishna or any of His authorised incarnations and expansions is not valid and being bogus is totally situated in tama guna. If such activities were anyway somehow or other able to be clandestinely orchestrated by unqualified schemers it would still have no efficacy due to the absence of devotion to Lord Krishna and lack of faith in the absolute authority of the Vedic scriptures.