The supreme enjoyer of all sacrifices accepted the incarnation of a boar [the second incarnation], and for the welfare of the earth He lifted the earth from the nether regions of the universe.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
द्वितीयं तु भवायास्य रसातलगतां महीम् । उद्धरिष्यन्नुपादत्त यज्ञेशः सौकरं वपुः
dvitīyaṃ tu bhavāyāsya rasātalagatāṃ mahīm | uddhariṣyannupādatta yajñeśaḥ saukaraṃ vapuḥ
SB 1.3.7