Sai Baba instructed the author to perform His service. What did He say about the true nature of this worship and His own form?

In Chapter 3, after telling the author to perform His service, Sai Baba explained the nature of true worship. He clarified that His physical body is perishable, but the true object of worship is the imperishable Brahman. Baba identified Himself with this ultimate reality, stating, "I am filled on all four sides in the form of the eightfold nature (Ashtadha-prakriti)." He explained that He is present in everything in the universe, both moving and unmoving, and that true service involves recognizing this omnipresence. This understanding, He said, leads to the dissolution of 'I' and 'mine,' where all desires cease.