The quality of chanting dpends on purity. Purity is dependent upon surrender. Chanting and Surrender happen simultaneously.
The study of Bhagavad Gita is for bhagvad darshan. The darshan that we get of the Lord is the essence of Bhagavad Gita.
If one renders even a small amount of sincere devotional service, Krishna becomes obliged to elevate such a person and what to speak of one whose entire life and soul has been dedicated to Krishna's service.
When we become advanced, we recognize the service of other devotees and we develop our appreciation for them and it manifests in the form of friendship.