Why did Sai Baba refuse to give the woman a secret mantra or 'upadesh'?

Sai Baba explained his refusal to give a secret mantra, or 'upadesh', by sharing his own experience with his Guru. As recounted in Chapter 19, Baba's own Guru never imparted a secret 'ear-mantra' to him. Instead, his Guru nurtured and protected him with a powerful, loving gaze, which Baba compares to a mother tortoise caring for her young from the opposite riverbank through sight alone. He tells the woman, "my Guru did not blow any mantra into my ears, so how can I blow one into yours?" He advised her not to be sad, but to simply "pay attention to me, and spiritual wealth will come into your hands," suggesting that focused devotion is more valuable than a secret instruction.