Valmiki Ramayana Bala Kanda Sarga 37 Shloka 25
Original Shlokaततस्तु देवता स्सर्वा: कार्तिकेय इति ब्रुवन्।।1.37.25।। पुत्रस्त्रैलोक्यविख्यातो भविष्यति न संशय:।4
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तत: thereafter, सर्वा: all, देवता: devatas, पुत्र: son, कार्तिकेय: इति as Karthikeya, son of Krittikas, त्रैलोक्यविख्यात: renowned in three worlds, भविष्यति shall become, संशय: न no doubt, इति ब्रुवन् thus spoke.
Thereafter, all the gods said, 'This son shall become renowned in the three worlds as Karttikeya, (son of krittikas). There is no doubt '.