In spite of possessing imperfect senses, people are proud of their knowledge. That is mistake. We are not concerned with imperfect knowledge. We want perfect knowledge. Therefore we are going to Bhagavad-gita. Otherwise what is the use? If it is an ordinary book - you can interpret in your own way, I can interpret in my own way - then what is the value of Bhagavad-gita with other books? No. It is not like that. Therefore the words of Krsna should be understood through the devotees: perfect channel. Krsna says, imam vivasvate yogam proktavam aham avyayam [Bg. 4.1]. Avyayam,... It is eternal. It is spiritual, avyayam. Avyayam means "that does not perish."
Lecture on Bhagavad-gita 4.2, Bombay, March 22, 1974