Acharya Prashant explains that spiritual practice, or Sadhana, loses its value if its duration and outcome are clearly known beforehand. If one knows exactly how long to practice and what the result will be, it becomes a mere transaction, similar to paying bank installments. The true value of Sadhana lies in the uncertainty of the journey, where one does not know the direction, the duration, or even who will remain at the end of the process. It is not based on logical proof or belief but on faith. He compares this journey to driving a vehicle through dense fog, where progress is slow and visibility is minimal, yet one must keep moving forward because there is no alternative. Seeking precise evidence of progress often becomes an excuse to stop the journey altogether.