Why would a being like Sai Baba, who is beyond birth and death, even take a physical form in the first place?

Chapter 43 explains that great souls and avatars incarnate for a singular, selfless purpose. The text states that they take on a physical form with the 'sole desire for the welfare of devotees' and 'for the sake of helping others.' Sai Baba's appearance in Shirdi is described as being 'gathered by the past merits of devotees' specifically for their protection and to complete a task on their behalf. These beings, personifications of Brahman, are not bound by the karmic cycle. Their incarnation is a voluntary act of grace. Once their mission for the 'welfare of people' is accomplished, they merge back into their true, unmanifest form.