This world can never make you happy,

This world can never make you happy, it's impossible. 
It may appear to make you happy for a while because you're gaining something that you want.

 But it will only last a short time. 
True happy ... true happiness comes from nothing. 

When your happiness arises from nothingness then you're really happy, because nothing made you happy and nothing can take it away.

 If something makes you happy then if something take it away you will be miserable. 

But if you learn to achieve happiness from nothing this is everlasting. It will never leave you because there is nothing to change.

The same is true for peace of mind.
 If you want peace of mind stop reacting to life's situations.

 Turn within to yourself. 
Nothing can keep you back from knowing yourself except you. 

Know yourself! 
Who am I? 
Where did I come from?
 What is the cause of the I? 

These questions must be pondered within yourself and inquired within the self over and over again.

 In all situations at all times. Do not think about what I'm saying to you.

 When you think about it you spoil it. 
Do not accept anything I'm saying to you.

 If you accept it there will be a fight within yourself. 
Your ego will fight you at every turn. 

So how are you to react to me? 

You're not to react to me at all.

Listen to the words I speak to you.
 Just become still within yourself.
 Never attempt to analyze anything I say.
 Empty yourself, and the truth of life will be revealed to you. 

Get rid of this extraneous knowledge and then you will know. Remember you do not know by acquiring knowledge, you know by getting rid of the knowledge.

 When you are empty you will know. As long as you are filled with knowledge then you will know relative knowledge of this world, but you will never know the truth of your existence, of who you are, where you came from. 
With all these things you have to be empty, not full.
-- Robert Adams, T225: Who Were You Before You Were Born?