I noticed this hidden door today in a hotel conference room. 

At first glance it is easy to just see a wall. With a little more attention we can see the door in the wall. This made me think about things that are hidden, and how we find them. 

Sometimes we need a guide who can show us hidden things, such as Geshe-la who revealed the direct meaning of the Heart Sutra and also its hidden meaning in the book New Heart of Wisdom. 

It is important to rely upon a qualified spiritual guide who understands all teachings thoroughly, and who has the skill to explain them to us in ways we can easily understand.