Why are Faith (Nishtha) and Patience (Saburi) described as 'two sisters' in the spiritual journey?

In Chapter 19, Faith (Nishtha) and Patience (Saburi) are described as "two sisters, dear as life to each other," highlighting their inseparable and mutually reinforcing nature in the spiritual journey. They are the 'two paise' the Guru seeks, signifying they are the fundamental price of admission to true discipleship. Faith provides the unwavering trust in the Guru and the path, while patience provides the endurance to stay on that path through all difficulties. The text reinforces this by noting that a powerful Guru still expects from the disciple "strong faith at the Guru’s feet and the strength of courage which is patience." Their description as sisters implies that one cannot exist meaningfully without the other; faith without patience may waver, and patience without faith lacks direction.