Dogen instructed,

There is a proverb about the way of the emperor, “If one’s heart is not empty, it is impossible to accept loyal advice.” What this means is that without holding personal views, one follows the opinions of loyal ministers and carries out the way of the sovereign according to how things should be. 

The attitude of Zen monks practicing the Way should be the same.  If you hold on to personal views even slightly, the words of your teacher will not enter your ears.  If you don’t listen to your teacher’s words, you cannot grasp your teacher’s dharma.  Forget not only the different views on the dharma, but also worldly affairs, and hunger and cold as well.  When you listen being completely purified in body and mind, you will be able to hear intimately.  When you listen with this attitude, you will be able to clarify the truth and resolve your questions.  True attainment of the Way is casting aside body and mind and following your teacher directly.  If you maintain this attitude, you will be a true person of the Way.  This is a primary secret. (Shobogenzo Zuimonki, Book 6, Chapter 17).