Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 17: Brahmā Orders the Demigods to Incarnate and Assist Rāma
Text 1.17.16

मारुतस्यात्मजः श्रीमान्हनुमान्नाम वानरः।
वज्रसंहननोपेतो वैनतेयसमो जवे।
सर्ववानरमुख्येषु बुद्धिमान्बलवानपि॥

mārutasyātmajaḥ śrīmān hanumān nāma vānaraḥ
vajra-saṁhananopeto
vainateya-samo jave
sarva-vānara-mukhyeṣu
buddhimān balavān api

mārutasya = of Vāyu; ātmajaḥ = the son; śrīmān hanumān = Śrīmān Hanumān; nāma = named; vānaraḥ = the monkey; vajra-saṁhanana-upetaḥ = was endowed with a body as unbreakable as the lightning; vainateya-samaḥ = equal to Garuḍa; jave = in speed; sarva-vānara-mukhyeṣu = among all the chief monkeys; buddhimān = he was intelligent; balavān api = and strong.

The son of Vāyu, the monkey named Śrīmān Hanumān, was endowed with a body as unbreakable as the lightning, equal in speed to Garuḍa. He was intelligent and strong among all the chief monkeys.

Though Lord Rudra was requested by Lord Brahmā to generate a son, because of his partiality towards the rākṣasa Rāvaṇa, he did not do so.