A strong mind.

It is not knowledge per se that which illumines the mind or pollutes it, expands it wisely or shrinks it stubbornly, but it is the state and capacity of the mind itself; that is, if the mind is kept pure and away from the seven capital sins, if the mind is self-aware of its own violence, if the mind is kept strong by good food and drink energy, then the mind is ready to absorb good knowledge and make the person truly wise. This is why some people who study and read, who have acquired much knowledge, are not wise at all; and so, they can display their intellects showing off their colorful feathers like a peacock, but when it comes to temptations and good actions they are weak and not an example of love at all.

You must understand that your mind and its capacity to absorb knowledge is the sum of all the things you do to keep it pure daily; for ‘pure’ in this case means clear, away from impressions which may disturb it and create unwelcome thoughts and images. A strong mind is able to access knowledge which strengthens reality, and when reality is strengthened then you internalize that knowledge and it gives you a confidence out of love which does not boast and which does not make you prideful.

The mind becomes prideful, arrogant, self-absorbed, when the knowledge is not internalized and it does not give you reality; so, when the knowledge you acquire gives you blind beliefs, fantastical imaginations, feelings of superiority in any way, then it means that something is wrong, it means that your mind is weak and that it is not properly nourished to absorb reality from knowledge–just like a seed (knowledge) planted into a barren and weedy field (the weak and polluted mind) cannot give good crop or any at all.