Can you explain the origin and practice of the 'Satya-Sai vow' as detailed in the source text?

The 'Satya-Sai vow' was a tradition initiated by the Patil out of gratitude for his miraculous healing. According to Chapter 13, just as people perform a Satyanarayan vow when in trouble, the Patil started this new practice dedicated to Sai. Every Thursday, after bathing, he would read from Das Ganu's 'modern Bhaktalilamrut.' Specifically, he would read the three chapters that sang of Sainath, considering this reading to be the 'Satya-Sai story.' This vow, performed with offerings and celebration, brought him and his relatives boundless happiness and peace. The text notes this tradition started by the Patil became a custom in the village.