4:4  

अर्जुन उवाच
अपरं भवतो जन्म परं जन्म विवस्वतः ।
कथमेतद्विजानीयां त्वमादौ प्रोक्तवानिति ॥४-४॥

arjuna uwaacha

aparaM bhawato janma paraM janma wiwaswataH ।

kathametadwijaaniiyaaM twamaadau proktawaaniti ॥४-४॥

Source: Automatic ITRANS Transliteration

Arjun said,
Recent is your birth, ancient the birth of Vivasvaan.
How am I to understand this: your declaration of this at the beginning?

Arjun said,
Your birth is recent, while Vivasvaan's birth is ancient. How am I to understand that you declared this [to him] at the beginning?

Source: Milind S. Pandit

Arjuna said: You were born later, but Vivasvaan was born in ancient time. How am I to understand that You taught this yoga in the beginning (of the creation)?

Source: The Bhagavad-Gita: The Sacred Song

Arjuna said: The sun-god Vivasvan is senior by birth to You. How am I to understand that in the beginning You instructed this science to him?

Source: Bhagavad Gita As It Is