Valmiki Ramayana Bala Kanda Sarga 27 Shloka 21
Original Shlokaस्थितस्तु प्राङ्मुखो भूत्वा शुचिर्मुनिवरस्तदा। ददौ रामाय सुप्रीतो मन्त्रग्राममनुत्तमम्।।1.27.21।।
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तदा thereafter, मुनिवर he exalted one among ascetics, शुचि having purified himself, प्रङ्मुखः turning his face towards east, स्थितः भूत्वा standing, सुप्रीतः wellpleased, रामाय for Rama, अनुत्तमम् preeminently best, मन्त्रग्रामम् collection of mantras, ददौ gave.
Viswamitra, the greatest ascetic after the purification ritual stood with his face turned east and happily, conferred on Rama collection of the unique mantras.