Having seen all these incidents in Bṛhadvana, Nanda Mahārāja became more and more astonished, and he remembered the words spoken to him by Vasudeva in Mathurā.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
दृष्ट्वाद्भुतानि बहुशो नन्दगोपो बृहद्वने । वसुदेववचो भूयो मानयामास विस्मितः
dṛṣṭvādbhutāni bahuśo nandagopo bṛhadvane | vasudevavaco bhūyo mānayāmāsa vismitaḥ
SB 10.7.33