aprajasya - of he who had no son; manoḥ - of Manu; pūrvam - formerly; vasiṣṭhaḥ - the great saint Vasiṣṭha; bhagavān - powerful; kila - indeed; mitrā-varuṇayoḥ - of the demigods named Mitra and Varuṇa; iṣṭim - a sacrifice; prajā-artham - for the sake of getting sons; akarot - executed; vibhuḥ - the great person.

Manu at first had no sons. Therefore, in order to get a son for him, the great saint Vasiṣṭha, who was very powerful in spiritual knowledge, performed a sacrifice to satisfy the demigods Mitra and Varuṇa.