To use what has a boundary to pursue what is limitless is...

To use what has a boundary to pursue what is limitless is dangerous; with this knowledge, if we still go after knowledge, we will run into trouble. Do not do what is good in order to gain praise. If you do what is bad be sure to avoid the punishment. Follow the Middle Course, for this is the way to keep yourself together, to sustain your life, to care for your parents and to live for many years.