Bhagavatapurana 8.7: atha saptamo'dhyāyaḥ

8.7.1

/0 śrīśuka uvāca
te nāgarājamāmantrya phalabhāgena vāsukim /
parivīya girau tasmin netramabdhiṃ mudānvitāḥ //

Śrī Śuka said:
Having invited Vāsuki, the king of serpents, by promising a share of the fruit, / and coiling him around that mountain as the churning rope, full of joy,

1. & 2. Sri Suka said:—They (the gods) invited Vasuki the king of Nagas, promised him a share in the benefit and bound the mount Mandara with him as with a rope; and gladly they began to churn the ocean for nectar with firm resolve, O best of Kurus; Sri Hari at first took hold of the fore part (i.e., the head of Vasuki) and the gods too went over to that side.

8.7.2

ārebhire surā yattā amṛtārthe kurūdvaha /
hariḥ purastāj jagṛhe pūrvaṃ devāstato 'bhavan //

the gods zealously set to work for the sake of the nectar, O leader of the Kurus. / Hari took hold of the head first, and the gods stood after Him.