What is the key to a strong Guru-disciple relationship, and how does it help one achieve spiritual non-duality?

According to the teachings in Chapter 19, the primary obstacle in the Guru-disciple relationship is the sense of difference, the feeling of 'I and Thou'. This is described as a wall that must be torn down to reach the state of non-duality. A devotee must recognize that the Guru, or God, is the ultimate master and protector ('Allah-Malik'). The chapter explains that our meeting with the Guru is a result of past karmic ties ('Rinanubandha') and should be cherished with mutual love to find happiness. While immense wisdom and faith are helpful, Chapter 19 states that gaining the Guru's strength, like Sai's, requires strong fortune. By dismantling the wall of ego and accepting the Guru's incomprehensible power, the path becomes clear and safe for the devotee.