When the cowherd woman [Kṛṣṇa’s foster mother, Yaśodā] was trying to tie the hands of her son with ropes, she found the rope to be always insufficient in length, and when she finally gave up, Lord Kṛṣṇa, by and by, opened His mouth, wherein the mother found all the universes situated. Seeing this, she was doubtful in her mind, but she was convinced in a different manner of the mystic nature of her son.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
गृह्णीत यद्यदुपबन्धममुष्य माता शुल्बं सुतस्य न तु तत्तदमुष्य माति । यज्जृम्भतोऽस्य वदने भुवनानि गोपी संवीक्ष्य शङ्कितमनाः प्रतिबोधिताऽऽसीत्
gṛhṇīta yadyadupabandhamamuṣya mātā śulbaṃ sutasya na tu tattadamuṣya māti | yajjṛmbhato'sya vadane bhuvanāni gopī saṃvīkṣya śaṅkitamanāḥ pratibodhitā''sīt
SB 2.7.30