Bhagavad Gita 4.5
श्री भगवानुवाच। बहूनि मे व्यतीतानि जन्मानि तव चार्जुन। तान्यहं वेद सर्वाणि न त्वं वेत्थ परन्तप।।4.5।।
śrī bhagavānuvāca| bahūni me vyatītāni janmāni tava cārjuna| tānyahaṃ veda sarvāṇi na tvaṃ vettha parantapa||4.5||
shri bhagavanuvaca bahuni me vyatitani janmani tava carjuna tanyaham veda sarvani na tvam vettha parantapa4.5
Meaning
Krishna explains: Both He and Arjuna have passed through many births. The difference is that Krishna remembers them all, while Arjuna does not. God's consciousness is unlimited.
श्रीभगवान् बोले — हे अर्जुन! मेरे और तुम्हारे बहुत से जन्म हो चुके हैं। हे परन्तप! उन सबको मैं जानता हूँ, पर तुम नहीं जानते।
This is verse 5 of 42 in Chapter 4 (Jnana Karma Sanyasa Yoga) of the Bhagavad Gita.