In Vedic culture, an acharya is a mahāpuruśa divine personality who is believed to have descended as an avatāra to teach and establish bhakti in the world and write on the siddhānta of devotion to Bhagawan , Lord Krishna.
By studying the character, life and literary works of a great Vaishnava acharya, one can derive deep understanding of how to lead one’s life in such a way that devotion to God becomes manifest in the heart.
The Founder-acharya is distinguished from all other acharyas, and his qualities and activities are outlined in the shastras:
Among all acharyas, certainly he who is the deliverer of all people, who appears in this world for the purpose of removing the fears of the fallen souls (dina-abhaya ) is the most perfect.
He sheds light on the ultimate meaning of the philosophical conclusions spoken by Krishna, who is the speaker of Bhagavad-gita. He also gives perfect purports to the evidences given by the rishis.
He propagates everywhere the meanings and purports of the songs of the previous acharyas. He, the ocean of mercy, contributes great books for the welfare of the people that explain the meaning of Vedanta strictly in line with the previous Vaishnava acharyas and devotees. In this way he conquers all, defeating hundreds of different kinds of inauspicious philosophies by his arguments.
Because of engaging in the welfare of the people of the world, that perfect and topmost mendicant is certainly the most important Founder acharya (pradhana). (Prapannamrita Tarpana 62.47-53)
Just as Vyasadeva is recognized as acharya because he presented the Vedic literatures, so Srila Prabhupada is recognized as acharya because of his making the Vedic literatures accessible to every man all over the world, and no one since has been able to contribute anything so significant. Rather, everyone is borrowing from him-his books are the standard.