"When the student is ready the teacher appears"
You can tell how powerful a quote is by how many people on the internet try to claim it for their own. A quick internet search will reveal that this particular saying has been attributed to both Taoism and Buddhism. There are variations, some people use sage or master in place of teacher. but the context is always the same.
When I first heard this quote, I thought that it alluded to some kind of strange cosmic ordering. Like Aladdin rubbing a lamp, your teacher would magically appear.... genie-like.
The truth is far more subtle and compelling.
The teacher is not a person, but a metaphor for the nature of reality. This simple saying is a call for everyone to learn from life itself. For there are lessons to be had everywhere - not just from everyone, but everything, and also your reaction to everyone and everything. It is a call for true mindfulness, to awaken from your torpor. For when you are ready to learn from life, it is life itself that becomes your teacher on a profound basis.