Can you explain the relationship between devotion to the 'Saguna' (form) and understanding the 'Nirguna' (formless) aspect of God as detailed in Chapter 52?

Chapter 52 posits that devotion to the Saguna, or the physical form of the Guru, is the essential gateway to realizing the formless divine. It states, 'Without entering the Saguna form, the light of the Self cannot be known; The Parabrahma, which is without attributes, is entirely difficult to understand.' This means that meditating on Sai's physical form is the prescribed method to eventually grasp the formless. The chapter explains that as one meditates immensely on the form, the 'Saguna vanishes' and the 'subtle nature of the Self will manifest,' leading the devotee from the manifest to the unmanifest reality.