This is the way of the parampara system. If we follow the acaryas, we attain the same benefit as our predecessors. If one follows the decisions of Arjuna, he should be considered to be directly hearing Bhagavad-gita from the Supreme Personality of Godhead. There is no difference between hearing Bhagavad-gita directly from the Supreme Lord and following a personality like Arjuna, who formerly heard Bhagavad-gita directly from the Lord. Sometimes foolish people argue that since Krsna is not present at the moment, one cannot take direct instructions from Him. Such foolish people do not know that there is no difference between directly hearing Bhagavad-gita and reading it, as long as one accepts Bhagavad-gita as it is, spoken by the Lord. However, if one wants to understand Bhagavad-gita by his imperfect interpretations, one cannot possibly understand the mysteries of Bhagavad-gita, even though one may be a great scholar according to mundane estimation.
(Srimad Bhagavatam 4.30.10)