Mahabharata 12.333.19

पिता पितामहश्चैव तथैव प्रपितामहःअहमेवात्र विज्ञेयस्त्रिषु पिण्डेषु संस्थितः

pitā pitāmahaścaiva tathaiva prapitāmahaḥahamevātra vijñeyastriṣu piṇḍeṣu saṃsthitaḥ

Our plain-language meaning of this verse is waiting for scholar review.