Valmiki Ramayana Aranya Kanda Sarga 3 Shloka 7
Original Shlokaतपसा चाभिसम्प्राप्ता ब्रह्मणो हि प्रसादजा। शस्त्रेणावध्यता लोकेऽच्छेद्याभेद्यत्वमेव च।।3.3.7।।
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तपसा through penance, ब्रह्मणः from Brahma, प्रसादजा bestowed by his pleasure, लोके in this world, शस्त्रेण with any weapon, अवध्यता not to be killed, अभिसम्प्राप्ता has been acquired, अच्छेद्याभेद्यत्वमेव च not to be cut or broken by any.
By the grace of Lord Brahma I was bestowed with this prowess through my penance. In this world none can kill me with a weapon nor split nor cut me to pieces.