Ramayana
ततो लोकत्रयं जित्वा स्थाप्य नागान्सुरान्वशे । समुद्रममृतार्थं च मथिष्यामि रसालयम् ॥ 7-20-19 ॥
"Then, having conquered the three worlds and brought the Nagas and the gods under my control, I shall churn the ocean, the abode of waters, for the sake of the nectar of immortality."
english translation