Valmiki Ramayana Bala Kanda Sarga 49 Shloka 15
Original Shlokaसा हि गौतमवाक्येन दुर्निरीक्ष्या बभूव ह।।1.49.15।। त्रयाणामपि लोकानां यावद्रामस्य दर्शनम्।
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सा she, गौतमवाक्येन with the words of Gautama, रामस्य Rama's, दर्शनम्यावत् till the appearance of Rama, त्रयाणामपि लोकानाम् even for three worlds, दुर्निरीक्ष्या incapable of being seen by any, बभूव ह became.
By the words of Gautama, she became invisible to the three worlds till the appearance of Rama.