How can writing or reading about a Guru's life be considered a form of service?

Chapter 0 explains that studying and performing Parayans of a detailed, poetic Guru biography is a significant form of Guru service. When a devotee writes such a biography, they perform Guru service. Simultaneously, when other devotees study and perform Parayans of that work, the writer gains the additional merit of serving God in humanity, referred to as Jan-Janardan. This is one of the two ways the Sadguru takes service from his devotees through books, allowing both the writer and the readers to fulfill the purpose of their lives.