One verse

Srimad Bhagavatam 9.6.14

9.6.14

वचनाद् देवदेवस्य विष्णोर्विश्वात्मन: प्रभो: । वाहनत्वे वृतस्तस्य बभूवेन्द्रो महावृष: ॥ १४ ॥

vacanad deva-devasya visnor visvatmanah prabhoh vahanatve vrtas tasya babhuvendro maha-vrsah

vacanat
by the order or the words
deva-devasya
of the Supreme Lord of all demigods
visnoh
Lord Visnu
visva-atmanah
the Supersoul of the entire creation
prabhoh
the Lord, the controller
vahanatve
because of becoming the carrier
vrtah
engaged
tasya
in the service of Puranjaya
babhuva
he became
indrah
the King of heaven
maha-vrsah
a great bull.

Puranjaya agreed to kill all the demons, on the condition that Indra would be his carrier. Because of pride, Indra could not accept this proposal, but later, by the order of the Supreme Lord, Visnu, Indra did accept it and became a great bull carrier for Puranjaya.