How does Sai Baba strengthen a devotee's faith according to the provided text?

According to Chapter 29, Sai Baba strengthens a devotee's faith through a process of testing and purification. The text uses the analogy of an oil-press peg that is first shaken and then fixed firmly to illustrate this method. It is explained that this is Baba's constant practice. A devotee's path may start sweetly but will encounter difficulties, which are described as tests. These trials are designed to make faith firm. Chapter 29 clarifies that although these tests might cause doubt, enduring them with perseverance is how Sai refines a devotee's devotion and strengthens their faith in him.