Ahus Tvam Rishayah Sarve

Arjuna strengthens his declaration with evidence. He says: this is not my opinion alone. The greatest sages have said the same — Narada, Asita, Devala, and Veda Vyasa himself. And now You are confirming it directly. Three lines of evidence converge: the ancient tradition, the words of the sages, and the teacher's own testimony.

Vyasa's mention here carries a unique poetic dimension. Vyasa is the author of the Mahabharata, within which the Gita exists. Arjuna cites Vyasa as an authority — and this citation is itself written by Vyasa. The author becomes a character in his own work, vouching for the truth he is recording.

This is the second part of the 10.12-13 pair. In 10.12, Arjuna listed Krishna's attributes. In 10.13, he provides authorities. This is a graceful union of faith and reasoning within the Gita.

Vyasa is also named as one of Krishna's vibhutis later, in 10.37. This creates an internal thread: in 10.13, Arjuna cites Vyasa as a witness; in 10.37, Krishna claims Vyasa as His own manifestation.