Can you explain the metaphor of the 'peg of an oil-press' mentioned in the Satcharitra in relation to a devotee's faith?

The metaphor of the 'peg of an oil-press' is a powerful illustration of how Sai strengthens a devotee's faith. As described in Chapter 29, this peg is first shaken around before it is firmly fixed in place. In the same way, Sai sometimes 'shakes' a devotee with various trials, difficulties, and tests that may cause mental doubt and dispositional shifts. This unsettling process is not meant to harm but to refine and purify the devotee's faith. By enduring this shaking, the devotee's devotion becomes stronger and is ultimately fixed firmly at the Guru's feet, unshakeable by future challenges.