Can you explain Sai Baba's analogy of the 'tortoise-vision' or 'Kurma-drishti'?

Sai Baba uses the powerful analogy of the 'tortoise-vision' in Chapter 19 to explain the nature of a Guru's grace. He describes a mother tortoise on one bank of a river whose young are on the opposite side. The mother does not provide milk or warmth in a physical sense; she simply nourishes her children with her loving gaze. The young ones, in turn, constantly meditate on their mother, and this remembrance alone is their complete sustenance. Baba uses this metaphor to illustrate how a Guru cares for and spiritually nourishes disciples, even from a distance. The Guru's loving glance, or grace, is all that is required for the devotee's progress, provided the devotee maintains constant remembrance and meditation on the Guru.