Bhagavad Gita 4.1
Lord Shri Krishna said: I taught this imperishable philosophy to Vivaswān, the founder of the Sun dynasty; Vivaswān gave it to Manu, the lawgiver, and Manu to King Ikshvāku.
श्री भगवानुवाच
इमं विवस्वते योगं प्रोक्तवानहमव्ययम्।
विवस्वान् मनवे प्राह मनुरिक्ष्वाकवेऽब्रवीत्॥śrī bhagavānuvāca
imaṃ vivasvate yogaṃ proktavānahamavyayam|
vivasvān manave prāha manurikṣvākave'bravīt||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).