Skanda Purana — Mahesvara Khanda, Shloka 19
ततो गायत्रिपूतं यद्द्विजास्तोयं क्षिपंति च । तेन दह्यंति ते पापाः संध्योपासनतः सदा
tato gāyatripūtaṃ yaddvijāstoyaṃ kṣipaṃti ca | tena dahyaṃti te pāpāḥ saṃdhyopāsanataḥ sadā
Then the water cast forth by the twice-born—purified by the Gāyatrī—burns those sinful beings; thus, through constant twilight worship they are ever scorched.
Lomaharṣaṇa (Sūta) to the sages (deduced)
Scene: A twice-born worshipper at riverbank at twilight, holding kuśa and water-vessel, offering arghya; the water, luminous with Gāyatrī, becomes a fiery stream that scorches embodied sins depicted as dark shadow-forms retreating.
FAQs
Daily discipline (sandhyā) empowered by mantra (Gāyatrī) is depicted as a real spiritual force that destroys inner and outer negativity.
No particular site is named; the merit is tied to the universal rite of sandhyā and arghya.
Offering/casting water sanctified by Gāyatrī during sandhyā (arghya), as part of regular twilight worship.