Devibhagavatapurana 3.30.55

3.30.55

prārthitastu suraiḥ sarvai rāvaṇenātipīḍitaiḥ |
kapayaste sahāyā vai devāṃśā balavattarāḥ ||

These powerful monkeys, born as Deva incarnates, all endowed with great power by Me, will help you. Your younger Laksmana is the incarnate of S’esa serpent; this indomitable man will kill undoubtedly Indragit, the son of Râvana.