Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 49
Sanskrit:
श्रीराजोवाचब्रह्मन् परोद्भवे कृष्णे इयान् प्रेमा कथं भवेत् ।योऽभूतपूर्वस्तोकेषु स्वोद्भवेष्वपि कथ्यताम् ॥ ४९ ॥
ITRANS:
śrī-rājovācabrahman parodbhave kṛṣṇeiyān premā kathaṁ bhavetyo ’bhūta-pūrvas tokeṣusvodbhaveṣv api kathyatām
Translation:
King Parīkṣit said: O brāhmaṇa, how could the cowherd women have developed for Kṛṣṇa, someone else’s son, such unprecedented pure love — love they never felt even for their own children? Please explain this.