Why is it said that spiritual progress is impossible without Shraddha and Saburi?

The text asserts this as a firm scriptural truth. As explained in Chapter 2, the path to spiritual knowledge requires a guide, or Guru, a principle so fundamental that even divine incarnations like Krishna submitted to one. Following this, the text introduces two more non-negotiable conditions: faith (Shraddha) and patience (Saburi). It declares that without them, "Not a bit of the spiritual goal is achieved." This implies that the spiritual path is not one of intellectual debate or competition, but one of humble trust and steadfast endurance, which are the very essence of Shraddha and Saburi.