इत्यहं वासुदेवस्य पार्थस्य च महात्मनः।संवादमिममश्रौषमद्भुतं रोमहर्षणम्॥
ity ahaṃ vāsudevasya pārthasya ca mahātmanaḥsaṃvādam imam aśrauṣam adbhutaṃ roma-harṣaṇam
Word by word
The verse says
Sanjaya said: so I have heard this conversation between Krishna and the great-souled son of Pritha, wonderful, and enough to make the hair stand up.
In plain words
The frame returns. We have not been listening directly all this time.
Sanjaya has been reporting the whole thing to a blind king sitting far away from the field.
And his first reaction is physical. Not an argument, not a conclusion. The hair standing up on his arms.
Where you've felt this · in friendship
You hear a piece of news secondhand from someone who was in the room, and it is their face rather than the information that tells you how serious it was. You did not see anything. You are nevertheless certain about what happened.
Going deeper
Remembering that this entire book is a report, delivered to someone who could not be there, changes how its ending reads.
Sanjaya is speaking to Dhritarashtra, a blind king who wanted to know what was happening to his sons. Everything from 1.1 onwards has been inside that report, which means the reader has been in the same position as the king throughout: receiving it from someone else, unable to verify it.
That is probably deliberate. A text that wanted unquestioning acceptance would not keep reminding you that it comes at second hand. This one puts the chain of transmission in the frame and leaves it visible.
Sanjaya's response is also worth noting for what it is not. He does not summarise the argument or say which school he favours. He reports an effect on his body, which is the sort of evidence nobody can check and everybody understands.