Bhagavad Gita Chapter 4.5
sri-bhagavan uvaca
bahuni me vyatitani
janmani tava carjuna
tany aham´ veda sarvan?i
na tvam´ 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!