How did not receiving a mantra from his Guru influence Baba's emphasis on faith and patience?

Sai Baba's experience of serving his Guru for twelve years without receiving a secret mantra, or 'upadesh,' was fundamental to his teachings. As described in Chapter 19, instead of a mantra, Baba learned that complete devotion, expressed as faith and patience, was the true path. He would gaze at his Guru's face constantly, feeling "neither hunger nor thirst." He later told a devotee that since his own Guru did not give him a mantra, he could not give her one. Instead, he compared his Guru's protection to a mother tortoise nurturing her young with only her gaze, concluding that the devotee should simply "pay attention to me, and spiritual wealth will come into your hands," thus prioritizing sustained faith over a singular instruction.