Bhagavad Gita
4.5

श्रीभगवानुवाच | बहूनि मे व्यतीतानि जन्मानि तव चार्जुन | तान्यहं वेद सर्वाणि न त्वं वेत्थ परन्तप ||५||

śhrī bhagavān uvācha bahūni me vyatītāni janmāni tava chārjuna tāny ahaṁ veda sarvāṇi na tvaṁ vettha parantapa

Translation

The Personality of Godhead said: Many, many births both you and I have passed. I can remember all of them, but you cannot, O subduer of the enemy!

Interpretation

Krishna declares that both he and Arjuna have had countless previous births. The difference: Krishna remembers all of his — because his consciousness is not limited by the ego that forgets past lives. Arjuna does not remember because his awareness is still filtered through the individual ego. This is the difference between the liberated and the bound.