Swami Vishwananda tells you today:

After the battle of Kurukshetra, Arjuna and Krishna were walking together in the fields. Krishna raised his hand and said to Arjuna, “Look at these birds in the sky how nice they are!”
“Yes”, answered Arjuna, looking in the sky.
“But there are no birds”, said Krishna.
“No, there are no birds”, answered Arjuna.
“Look how nice these birds are”, said again Krishna. “They are really magnificent.”
“Yes”, said Arjuna. “These birds are really magnificent.”
“Why are you always repeating what I am saying?” asked Krishna, “There are no birds in the sky.”
“Yes, it is true. I don’t see any birds in the sky but I know that you could manifest at every moment, these birds and let them fly in the sky.”
Arjuna had total faith in Krishna and had totally surrendered body, mind and soul to the Divine. He was not trusting his mind or his eyes but he trusted every word from his Divine Sadguru.