Mahabharata 12.146.2

भीष्म उवाच · bhīṣma uvāca

अत्र ते वर्णयिष्येऽहमितिहासं पुरातनम्इन्द्रोतः शौनको विप्रो यदाह जनमेजयम्

atra te varṇayiṣye'hamitihāsaṃ purātanamindrotaḥ śaunako vipro yadāha janamejayam

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