Skandapurana 5.242.49

5.242.49

mā bhūtsaṃśayastenātra nā''pnuṣe saṃśayātphalam ..
śāligrāmārcanaparāḥ śuddhadehā vivekinaḥ .. 49 ..

Let there be no doubt in you about this; one does not obtain the fruit [of rites] through doubt. / Those devoted to the worship of the Śāligrāma, of pure body and possessing discernment, 49