How important is a Guru for developing faith, according to the provided text?

According to the preface of the Shri Sai Satcharita, a Guru is presented as absolutely essential for spiritual progress and crossing the ocean of life. The text uses the example of the author, Annasaheb, who, as mentioned in an account from the third chapter, initially had no Guru devotion and even thought the practice was a fraud. However, chapter 0 explains that this pride was completely shattered when his eyes met Baba's. This transformative encounter made him fully convinced that there is no way to navigate life's challenges without a Sadguru, highlighting the pivotal role of a Guru in fostering faith.