According to the teachings, how can one cultivate faith and achieve spiritual goals through service to a Guru?

The Preface (Chapter 0) explains that the most certain path to salvation is through dedicated service to one's Sadguru. This involves writing the Sadguru's biography, either by their command or through inner inspiration, and then personally studying it. A devotee should perform hundreds of readings (Parayans) and weekly recitations (Saptahs) with a 'firm resolve, pure heart, excellent faith, selfless love, and unwavering devotion.' This form of service, which combines bodily and vocal actions, is said to cultivate profound faith and lead directly to the ultimate spiritual goal without interfering with one's worldly responsibilities.