Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 15

Sanskrit:

मुनौ निक्षिप्य तनयौ सीता भर्त्रा विवासिता ।ध्यायन्ती रामचरणौ विवरं प्रविवेश ह ॥ १५ ॥

ITRANS:

munau nikṣipya tanayausītā bhartrā vivāsitādhyāyantī rāma-caraṇauvivaraṁ praviveśa ha

Translation:

Being forsaken by her husband, Sītādevī entrusted her two sons to the care of Vālmīki Muni. Then, meditating upon the lotus feet of Lord Rāmacandra, she entered into the earth.

Purport:

It was impossible for Sītādevī to live in separation from Lord Rāmacandra. Therefore, after entrusting her two sons to the care of Vālmīki Muni, she entered into the earth.