In plain words
The poet, to the Lord: O Kēśava [father of Brahmā and Śiva], who became a tortoise living in the waters where the snares [of Varuṇa] lie! Your lying, from the time of creation, on the serpent [Ādiśeṣa] spread as your bed on the waters of the sea, without the least misgiving, while the gods who stand to speak your praise came and sang to you; and the way you lay that day [of the churning], bearing the mountain on your back, so that those who did not know your goodness scorned you: tell me these, so that I may understand.