Without self knowledge, without understanding the working and functions of his machine, man cannot be free, he cannot govern himself and he will always remain a slave.
Cannot Free Functions Govern Himself
If you want to lose your faith, make friends with a priest.
Friends Lose Make Priest Want
A man will renounce any pleasures you like but he will not give up his suffering.
Give His Like Man Pleasures
A "sin" is something which is not necessary.
Sin Something Which
Religion is doing; a man does not merely think his religion or feel it, he "lives" his religion as much as he is able, otherwise it is not religion but fantasy or philosophy.
Does Doing Fantasy Feel His
It is the greatest mistake to think that man is always one and the same. A man is never the same for long. He is continually changing. He seldom remains the same even for half an hour.
Changing Continually Even Greatest Half