Verse 4-4, Verse 4-5

अर्जुन उवाच |

अपरं भवतो जन्म परं जन्म विवस्वत: |

कथमेतद्विजानीयां त्वमादौ प्रोक्तवानिति || 4 ||

श्रीभगवानुवाच |

बहूनि मे व्यतीतानि जन्मानि तव चार्जुन |

तान्यहं वेद सर्वाणि न त्वं वेत्थ परन्तप || 5 ||

Arjuna said, “You were born after Vivasvat. How am I to understand that in the beginning You instructed this science of yoga to him?”
Sri Krishna replied, “Arjuna, you and I had many births. You have forgotten them, while I remember them all, O scorcher of foes.”

Commentary
God has compassionately covered the memory of previous lifetimes with a dark cover of Maya so that man does not get confused with the loves and losses of many fathers, mothers, siblings, spouses, friends and relatives. Only after the devotee qualifies spiritually, God reveals the previous births to the extent it is required. However just as a person remembers all the transitions of his life – as a child, growing to a young person, adult and an old man, Lord Krishna remembers his previous births and that of Arjuna as a continuous journey intermittently paused on earth due to death and resumed again in a new body. A supreme yogi like Lord Krishna can remain in a state of Eternal Now, knowing all past actions unfolding in the present and in the future. Any devotee who can light the spark of divinity in the dark inner sanctum sanctorum and merge with the eternal flame of Lord Krishna can attain a similar state of continuity in divine consciousness.