Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 30

Sanskrit:

श्रीशुक उवाचइति प्रणयबद्धाभिर्गोपीभि: कृतरक्षणम् ।पाययित्वा स्तनं माता सन्न्यवेशयदात्मजम् ॥ ३० ॥

ITRANS:

śrī-śuka uvācaiti praṇaya-baddhābhirgopībhiḥ kṛta-rakṣaṇampāyayitvā stanaṁ mātāsannyaveśayad ātmajam

Translation:

Śrīla Śukadeva Gosvāmī continued: All the gopīs, headed by mother Yaśodā, were bound by maternal affection. After they thus chanted mantras to protect the child, mother Yaśodā gave the child the nipple of her breast to suck and then got Him to lie down on His bed.

Purport:

When a baby drinks milk from the breast of his mother, this is a good sign of health. So the elderly gopīs were not satisfied with chanting mantras to give protection to Kṛṣṇa; they also tested whether their child’s health was in order. When the child sucked the breast, this confirmed that He was healthy, and when the gopīs were fully satisfied, they had the child lie down on His bed.