How did Sai Baba describe his relationship with his own Guru, and what did he learn from him?

Sai Baba described a profoundly loving and devoted relationship with his Guru, whom he called a 'great Auliya' and an 'ocean of mercy.' He served his Guru for twelve years, and as he recounts in Chapter 19, he gazed upon his Guru's face day and night, feeling neither hunger nor thirst, his mind completely absorbed in contemplation of him. Despite Baba's desire for a secret mantra, his Guru never gave him one. Instead, the Guru provided constant love, protection, and care, which Baba compares to a mother tortoise nurturing her young with her gaze alone. From this, Baba learned that the Guru's loving glance and constant presence are the true teachings, more powerful than any whispered instruction.