Valmiki Ramayana Aranya Kanda Sarga 32 Shloka 19
Original Shlokaमन्त्रैरभिष्टुतं पुण्यमध्वरेषु द्विजातिभिः। हविर्धानेषु यस्सोममुपहन्ति महाबलः।।3.32.19।।
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महाबलः mighty, यः he, अध्वरेषु during sacrifices, हविर्धानेषु at places fit for offering oblations, द्विजातिभिः by brahmins, अभिष्टुतम् extracted, मन्त्रै: by chanting Vedic hymns, पुण्यम् sacred, सोमम् Soma juice, उपहन्ति made impure.
The mighty Ravana defiled the sacred Soma juice, worthy of oblations, extracted by Brahmins by chanting mantras in scrifices.