Sanjaya said: Having spoken thus to Arjuna, Sri Krishna revealed to him once more His own form. The Great-minded One, assuming again a benign form, reassured him who was terrified.
Purport
On Request of Arjuna, Bhagvan Shri Krishna displayed his four-armed form and then he returns back to his Human form as he been incarnated in this Yuga as son of Vasudeva.
Sanjaya explains this to Dhrishtarashtra in the above shloka.
