Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 31: Viśvāmitra, Rāma and Lakṣmaṇa Depart for Mithilā
Text 1.31.10

धनुषस्तस्य वीर्यं तु जिज्ञासन्तो महीक्षितः।
न शेकुरारोपयितुं राजपुत्रा महाबलाः॥

dhanuṣas tasya vīryaṁ tu jijñāsanto mahī-kṣitaḥ
na
śekur āropayituṁ rāja-putrā mahā-balāḥ

dhanuṣaḥ tasya = of that bow; vīryam tu = about the power; jijñāsantaḥ = despite being inquisitive; mahī-kṣitaḥ = kings; na śekuḥ āropayitum = could not string it; rāja-putrāḥ = and princes; mahā-balāḥ = very powerful.

Despite being inquisitive about the power of that bow, very powerful kings and princes could not string it.