No one is fit to judge a book ...

No one is fit to judge a book until he has rounded Cape Horn in a sailing vessel, until he has bumped into two or three icebergs, until he has been lost in the sands of the desert, until he has spent a few years in the House of the Dead.
No one is fit to judge a book until he has rounded Cape Horn in a sailing vessel, until he has bumped into two or three icebergs, until he has been lost in the sands of the desert, until he has spent a few years in the House of the Dead.
 Van Wyck Brooks

More phrases

Being self-made is a state of mind, and once you put that mentality to work, your success will come.
 Dave East
A lot of people change for good. Some people just fall off. Just trying to progress in anything, no matter what you're doing, I feel like any progression you make... some people aren't gonna be around you that were around you.
 Dave East
What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.
Don't settle in the land of barely enough. That is where you are, it is not who you are. That's your location, it's not your identity. No matter what it looks like, have an abundant mentality.
Everything in your life, every experience, every relationship is a mirror of the mental pattern that is going on inside of you.

Quotes from the same author

How delightful is the company of generous people, who overlook trifles and keep their minds instinctively fixed on whatever is good and positive in the world about them. People of small caliber are always carping. They are bent on showing their own superiority, their knowledge or prowess or good breeding. But magnanimous people have no vanity, they have no jealousy, and they feed on the true and the solid wherever they find it. And what is more, they find it everywhere.
 Van Wyck Brooks