From Lilamrita:

After the plane had reached cruising altitude, a uniformed gentleman emerged from the cabin. Immediately he caught sight of Srila Prabhupäda sitting by the window and walked over. When he leaned over and asked Prabhupäda how he was, Prabhupäda saw that the man wanted to talk, so he asked Upendra to get up and give the gentleman his seat.

“You are the captain?” Prabhupäda surmised.

“No,” the man replied. “I am a flight supervisor, come to overlook the pilot and the crew. Would it be all right if I asked you a philosophical question?”

Prabhupäda nodded, apparently pleased.

“Is everything created by God?”

Srila Prabhupäda said yes and quoted the Vedänta-sütra: janmädy asya yatah. Everything in existence, Prabhupäda said, has its origin in God.

“Then what is evil?” the flight supervisor asked. “Is evil also God’s creation?”

“For God there is not good or evil,” Prabhupäda explained. “Everything is good. Goodness is God’s frontage, and evil is God’s back portion. Taking this example, the chest or the back of the body are equal. It is not that when there is some pain in the back side I don’t care for it, I simply take care of it when there is pain in the chest. No. Although it is the back side, it is as important as the front side.

“So evil and good are also of the same importance? No. For God there is nothing evil. Just like for the sun there is no darkness. But for us there is light and darkness. If you keep your back to the sun, you will find darkness. And if you face the sun, then there is no darkness.

“We create darkness as soon as we change our position. If instead of remaining in front of God I keep God on the back, then there is darkness. Otherwise, there is no question of darkness. But in the sun as it is, there is no such darkness. Therefore God is all-good. But for us, when we forget God, that is evil. And when we are in God consciousness always, then everything is good. Is that all right?”

The man seemed to understand and respectfully accepted the answer. He was about to ask another question when a well-dressed but somewhat drunken passenger came up to them and spoke. Srila Prabhupäda looked up at the man and asked, “Are you afraid of death?” The intoxicated man stammered, sobered, and walked away.

The flight supervisor inquired again, taking his meeting with Srila Prabhupäda as a rare opportunity. “Can you tell me how one can become peaceful?” he asked.

Srila Prabhupäda began quoting Bhagavad-gitä, bhoktäram yajna tapasäm…, and, signaling Visäkhä, asked for a copy of the Gitä. The devotees quickly consulted, but no one had a Bhagavad-gitä.

When Prabhupäda heard this he became angry, although containing his feelings in the presence of his guest. He then explained to the man that one had to have knowledge of God as the supreme controller, the supreme enjoyer, and the best friend of everyone; only then could one have peace. “Out of foolishness,” Prabhupäda said, “we are claiming the land is our property. Therefore there is no peace. But actually, God is the proprietor.”

Both Srila Prabhupäda and the flight supervisor enjoyed their talk, and as the flight supervisor excused himself, he heartily shook Prabhupäda’s hand.

Prabhupäda called for Pradyumna. His eyes glowing in transcendental anger, he reprimanded Upendra and Pradyumna for not having a copy of Bhagavad-gitä; they should have one with them at all times.

Pradyumna offered that although he didn’t have Prabhupäda’s Bhagavad-gitä As It Is, he just happened to be carrying an edition by another author. This infuriated Prabhupäda even more. He then ordered Upendra never to travel again without carrying three books: Bhagavad-gitä As It Is, and the first volume of Caitanya-caritämrta and Srimad-Bhägavatam.