Based on the provided text, what are the defining qualities of a Sadguru as described in Chapter 28?

Chapter 28 of the Shri Sai Satcharitra teaches that a Sadguru possesses profound and all-encompassing qualities. Firstly, a Sadguru like Sai is not separate from anyone but dwells in all beings, from the highest deity Brahma to the smallest ant. The chapter explains that a true Sadguru is proficient in both Shabda-Brahma (the divine word) and shows signs of the Para-Brahman (Supreme Being). A key attribute highlighted is the ability to impart teachings effectively to disciples. The text also presents a powerful comparison, stating that while a father gives birth to a body subject to death, the Guru's compassion is greater because a Sadguru has the power to remove the entire cycle of birth and death for the devotee.