Knowledge Through Disciplic Succession 49
Mahābhārata  we understand that  Bhagavad-gītā  was spoken to Arjuna some 5,000 years ago. Before Arjuna, the teachings were handed down by disciplic succession, but over such a long period of time, the teachings became lost.
evaṁ paramparā-prāptam imaṁ rājarṣayo viduḥ sa kāleneha mahatā yogo naṣṭaḥ parantapa
sa evāyaṁ mayā te 'dya yogaḥ proktaḥ purātanaḥ bhakto 'si me sakhā ceti rahasyaṁ hy etad uttamam
“This supreme science was thus received through the chain of disciplic succession, and the saintly kings understood it in that way. But in course of time the succession was broken, and therefore the science as it is appears to be lost. That very ancient science of the relationship with the Supreme is today told by Me to you because you are My devotee as well as My friend; therefore you can understand the transcendental mystery of this science.” (Bg. 4.2-3)
In  Bhagavad-gītā  a number of  yoga  systems are delineated— bhakti-yoga ,  karma-yoga ,  jñāna-yoga ,  haṭha-yoga —and therefore it is here called  yoga . The word  yoga  means “to link up,” and the idea is that in  yoga  we link our consciousness to God. It is a means for reuniting with God or re-establishing our relationship with Him. In the course of time, this  yoga  imparted by Śrī Kṛṣṇa was lost. Why is this? Were there