Can you explain the dual benefit that arises when a devotee writes and shares a Guru's biography?

When a devotee authors a detailed biography of their Guru, it results in a twofold spiritual benefit as described in Chapter 0. Firstly, the writer themselves is seen as performing a significant act of Guru service. Secondly, when other devotees study this work and perform Parayans, the writer accrues the additional merit of serving God in humanity (Jan-Janardan) and performing a valuable public service. This, in turn, helps those other devotees achieve the purpose of their own lives, magnifying the positive spiritual impact of the original act of writing.