IV: 2

Chapter 4, Verse 2

"And so the sages,
Who were kings,
In royal succession
Carried it onwards
Till at length it was lost,
Forgotten by humans."

Srila Prabhupada:

"The teaching was especially meant for the saintly kings as they executed its purpose while ruling. Five thousand years ago on the field of Kurukshetra it was stated by the Lord himself that the disciplic succession had been broken, and therefore Krishna declared that the teaching apparently had been lost."

Paramahansa Yogananda:

"Over the centuries, the knowledge of the science of Yoga declined and was forgotten. Nevertheless, as spirit is eternal, so Yoga, the art and science of reuniting the outgoing, differentiated soul-ray with the omnipresent spiritual Sun, also is everlasting. Even though almost completely buried, the spirit of Yoga can never be banished, for it is linked to the living reality in the heart of each of us. The laws by which we can recall the forgotten links exist eternally within us, dormant, ready to be quickened and then demonstrated."