Imagine that you had gone all your life without ever washing, and then one day you decide to take a shower. You start scrubbing away, but then watch in horror as the dirt begins to ooze out of the pores of your skin and stream down your body. Something must be wrong: You were supposed to be getting cleaner and all you can see is grime. You panic and fling yourself out of the shower, convinced that you should never have begun. But you only end up even more dirty than before. You have no way of knowing that the wisest thing to do is to be patient and to finish the shower. It may look for a while as if you are getting even dirtier, but if you keep on washing, you will emerge fresh and clean. It’s all a process, the process of purification.
Whenever doubt arises, see it simply as an obstacle, recognize it as an understanding that is calling out to be clarified or unblocked, and know that it is not a fundamental problem but simply a stage in the process of purification and learning. Allow the process to continue and complete itself, and never lose your trust or resolve. This is the way followed by all the great practitioners of the past, who used to say: “There is no armour like perseverance.” (View On Buddhism)