Brahmajalasutta 2.12.6

2.12.6

Idaṃ, bhikkhave, tatiyaṃ ṭhānaṃ, yaṃ āgamma yaṃ ārabbha eke samaṇabrāhmaṇā ekaccasassatikā ekaccaasassatikā ekaccaṃ sassataṃ ekaccaṃ asassataṃ attānañca lokañca paññapenti.

This is the third ground on which some ascetics and brahmins rely to assert that the self and the cosmos are partially eternal.