Valmiki Ramayana Aranya Kanda Sarga 9 Shloka 19

तदा then, तस्मिन् in that, आश्रमपदे at the hermitage, पुण्ये holy, तपसि in penance, तिष्ठतः practising, निशितः a sharp, उत्तमः best, सः खङ्ग: that sword, न्यासविधिना as a trust, दत्तः was deposited.

Then while the sage was practising penance at the hermitage, he gave him that excellent sword to be kept in trust.