Valmiki Ramayana Bala Kanda Sarga 37 Shloka 1
Original Shlokaतप्यमाने तपो देवे देवा: सर्षिगणा: पुरा। सेनापतिमभीप्सन्त: पितामहमुपागमन्।।1.37.1।।
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पुरा in the olden days, देवे when Iswara, तप: तप्यमाने engaged in austerities, सर्षिगणा: together with ascetics, देवा: devatas, सेनापतिम् army general, अभीप्सन्त: desirous of obtaining, पितामहम् lord Brahma, उपागमन् approached.
In olden days when Iswara was engaged in austerities, the devatas together with the ascetics, approached Lord Brahma for an army general. Birth of Karttikeya.