B.G 4.04
arjuna uvāca
aparaṁ bhavatō janma paraṁ janma vivasvataḥ। kathamētad vijānīyāṁ tvamādau prōktavāniti ॥4॥
Arjuna asked:
Recent in time is your birth, and remote in antiquity was the birth of Vivasvan. How then am I to understand that you taught it in the beginning?
Gīta Bhāshya 4.04
Arjuna is eager to gain additional understanding of the lord's greatness, which was previously proclaimed in verse 3.30.
"mayi sarvāṇi" ityuktaṁ tanmāhātmyamāditō jñātuṁ pr̥cchati - aparamiti ॥4॥
It is already said - "In me dedicate all actions" (3.30). To understand the origin of that greatness, Arjuna inquires through "aparam" verse.
Gīta Tātparya 4.04
Those who are wise ask questions to bring unique wisdom to the forefront of society.
jānantō'pi viśēṣārthajñānāya sthāpanāya vā। pr̥cchanti sādhavō yasmāt tēna pr̥cchasi pārthiva॥
"Even though they have previous understanding, the wise ask question about the special knowledge to establish, and to ascertain. Similarly, Arjuna inquired."
iti āgnēyavacanāt na arjunaḥ bhagavantaṁ na jānāti ॥4॥
From such statements of Agni Purāna, it becomes clear Arjuna is not asking because he doesn't know the Lord.
