As a disciple of Buddha Shakyamuni, our focus should not emphasize theory too much, but place more emphasis on how to put theory into practice. When we’re too focused on theory, our brains can get a little strange; slowly a gap will develop between the Dharma and our practice. Questions will crowd our mind. So we have to use the theories and put them in to practice, not just keep them in our heads. We need to use our mind to truly experience the philosophy and then we can clarify our doubts. Putting these ideas in to practice is the best way to clear away our doubts. Therefore, Shariputra asked how to practice and not for an explanation of emptiness.
In the Heart Sutra, we are taught a method to help us work on our mind. What is important is whether or not your mind has been worked on. If we have read many sutras and yet our minds have not changed at all or improved some, then that is a real pity. It is so sad that it makes you want to cry.
~Karmapa: The Heart Sutra Session Four – The View of Emptiness and the Path to Buddhahood