Skandapurana 2.7.0.p21

2.7.0.p21

adhyāyaḥ 21 vaiśākhamāsamāhātmyaśravaṇena sarpasya muktiḥ, tasyaiva pūrvajanmavṛttāntakathanam, śaṃkhavyādhasaṃvāde vyādhasya janmāntare vālmīkarṣitvaprāptikathanam

Chapter 21: The liberation of a snake by hearing the māhātmya of the month of Vaiśākha; the narration of its previous birth; in the dialogue of Śaṅkha and the hunter, the narration of the hunter attaining the status of the seer Vālmīki in another birth.