On the road of desire, do not happily dip your fingers into the pot just because it happens to be there.  

Once you have stuck them in and tasted what is inside, you will try to put them in ten thousand fathoms deep.

On the road of principle, do not step back even a little, hesitating over the difficulties.  

Once you have taken a single step back in fear, you will be separated from your goal by a thousand mountains.