How did Sai Baba teach his devotee Dev about faith and perception during the Udyapan ceremony?

The story of Dev's Udyapan ceremony, detailed in Chapter 40, serves as a profound lesson in faith. When Dev invited Baba, Baba promised to attend but a "veil of Maya" prevented Dev from recognizing him in the guise of a Sanyasi. Even after personally serving the three uninvited guests, Dev remained doubtful and wrote a letter expressing his disappointment that Baba had not come. Baba later explained through Jog that he had indeed been present, but Dev "did not recognize Me!" This incident taught Dev a powerful lesson about looking beyond physical appearances and having unwavering faith, as Baba's presence is not limited by a single form.