Skandapurana 7.20.3

7.20.3

prayāge ṛṣīṇāṃ sūtena samāgamaḥ, ṛṣīṇāṃ skandajanmaviṣayakaḥ praśnaḥ . sūtasya byāsasanatkumārasaṃvādamukhena skandotpattikathāvataraṇopakramaḥ .

The meeting of the seers with Sūta at Prayāga; the seers' inquiry regarding the birth of Skanda; the beginning of Sūta's recitation of the story of the birth of Skanda through the dialogue between Vyāsa and Sanatkumāra.