Although you may not have experienced the final development (enlightenment) yet, it is no big secret that there is a final development. You can't pretend that the Buddha didn't exist and still talk about his teachings, because he actually did it—he achieved enlightenment. We can't keep that a secret. In the meantime, however, you could regard any sense of promise that comes into your mind, any hope that comes up, as another thought. If there is a strong desire to achieve a result, that will push you back. You could relate to hope as respect for the dharma, or the truth, rather than a promise. It is like a schoolchild seeing a professor: one day she too might become a professor, but she still has to do her homework. Similarly, particularly in the hinayana, the early stage of the path, there is a journey going on all the time.
From Chapter Seven, "Meditation as the Path to Buddhahood," in The Truth of Suffering and the Path of Liberation, page 71.