Taking to Krṣṇa Consciousness
sa kāleneha mahatā
yogo naṣṭaḥ parantapa
sa evāyaṁ mayā te 'dya
yogaḥ proktaḥ purātanaḥ
bhakto 'si me sakhā ceti
rahasyaṁ hy etad uttamam
“I instructed this imperishable science of  yoga  to the sun-god Vivasvān, and Vivasvān instructed it to Manu, the father of mankind, and Manu in turn instructed it to Ikṣvāku. 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. 4.1-3)
That original spiritual disciplic succession was broken, but now we can receive the same message by studying  Bhagavad-gītā . In  Bhagavad-gītā  Krṣṇa speaks to Arjuna just as in a far distant time He spoke to the sun-god. If we accept the words of Arjuna and Krṣṇa, it may be possible for us to understand  Bhagavad-gītā , but if we want to interpret it in our own way, the results will be nonsensical. The best way to understand  Bhagavad-gītā  is to accept a bona fide spiritual master. This is not very difficult.