From The Collected Teachings of Ajahn Chah – Single Volume, 2011, p. 37.
I would like to ask you about your practice. You have all been practising meditaton here, but are you sure about the practice yet? Ask yourselves, are you confident about the practice yet? These days there are all sorts of meditation teachers around, both monks and lay teachers, and I’m afraid it will cause you to be full of doubts and uncertainty about what you are doing. This is why I am asking. As far as Buddhist practice is concerned, there is really nothing greater or higher than these teachings of the Buddha which you have been practising with here. If you have a clear understanding of them, it will give rise to an absolutely firm and unwavering peace in your heart and mind