yā niśā sarva-bhūtānāṁ
tasyāṁ jāgarti saṁyamī
yasyāṁ jāgrati bhūtāni
sā niśā paśyato muneḥ
"What is night for all beings is the time of awakening for the self-controlled, and the time of awakening for all beings is night for the introspective sage."
"There are two classes of intelligent men. The one is intelligent in material activities for sense gratification, and the other is introspective and awake for the cultivation of self-realization. Activities of the introspective sage, or thoughtful man, are night for persons materially absorbed. Materialistic persons remain asleep in such a night due to their ignorance of self-realization. The introspective sage remains alert in the 'night' of the materialistic men. The sage feels transcendental pleasure in the gradual advancement of spiritual culture, whereas the man in materialistic activities, being asleep to self-realization, dreams of varieties of sense pleasure, feeling sometimes happy and sometimes distressed in his sleeping condition. The introspective man is always indifferent to materialistic happiness and distress. He goes on with his self-realization activities undisturbed by material reaction."
Mr. Asnani: Prabhupāda, in this stanza, I have not followed a little. That stanza which he just read it. Now, a spiritual bent of mind person, he sleeps in the daytime. I mean the...
Prabhupāda: Materialist person...
Mr. Asnani: He sleeps in the nighttime, and there's trouble in his thoughts. Whereas a spiritual man, he's awoken in the nighttime and sleep in the daytime.
Prabhupāda: First of all let us understand what is sleeping and awakening. This is the real understanding. The materialistic man, he's sleeping about self-realization. He has no information.
Mr. Asnani: He has no?
Mr. Asnani: Yes, sure.
Prabhupāda: But the spiritualistic man, he's awakened in that, that this life is meant for self-realization. So the materialistic man, he does not know. He's kept in darkness of night. And the spiritualistic man is awakened. That is the difference.
Mr. Asnani: Why the day and the night...?
Prabhupāda: Night means ignorance, when one sleeps.
Mr. Asnani: Oh, night like ignorance; day is awakened.
Prabhupāda: Yes. And day is awakening. So what is day for the materialistic person, so that is night for the spiritualistic person. And what is day for the spiritualistic person, that is night for the... Just like a spiritualist person, he has sacrificed everything and he is after God, and they are thinking, "These rascals, unnecessarily, empty stomach, wasting, 'Kṛṣṇa, Kṛṣṇa, Hare Kṛṣṇa,' chant." They are deriding. And he is thinking that "This rascal got this human form of body. Instead of spiritual culture, he's spoiling his life, cats and dogs." That means in the subject matter where the spiritualists were not interested, he is interested. And in the subject matter, the spiritual person, interested, he is not interested. This is day and night.
Mr. Asnani: Oh, I was taking sometime in literary senses. So it was sometimes confusing me.
(Srila Prabhupada Conversation, Bombay, January 8, 1977)