Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 3
Sanskrit:
चुक्रुशुस्तमपश्यन्त: कृष्ण रामेति गोपका: । भगवांस्तदुपश्रुत्य पितरं वरुणाहृतम् । तदन्तिकं गतो राजन्स्वानामभयदो विभु: ॥ ३ ॥
ITRANS:
cukruśus tam apaśyantaḥkṛṣṇa rāmeti gopakāḥbhagavāṁs tad upaśrutyapitaraṁ varuṇāhṛtamtad-antikaṁ gato rājansvānām abhaya-do vibhuḥ
Translation:
O King, not seeing Nanda Mahārāja, the cowherd men loudly cried out, “O Kṛṣṇa! O Rāma!” Lord Kṛṣṇa heard their cries and understood that His father had been captured by Varuṇa. Therefore the almighty Lord, who makes His devotees fearless, went to the court of Varuṇadeva.
Purport:
Viśvanātha Cakravartī Ṭhākura explains that when Nanda Mahārāja went to bathe in the river, he was accompanied by several cowherd men. When Nanda did not come out of the water, they began to cry out, and Lord Kṛṣṇa immediately came there. Understanding the situation, Śrī Kṛṣṇa entered the water and went to the court of the demigod Varuṇa, determined to free His father and the other cowherd men from fear of a mere demigod.