You think that a wall as ...

You think that a wall as solid as the earth separates civilization from barbarism. I tell you the division is a thread, a sheet of glass. A touch here, a push there, and you bring back the reign of Saturn.
 John Buchan

Quotes from the same author

Bethink you of the blessedness. Every wife is like the Mother of God and has the hope of bearing a saviour of mankind.
 John Buchan
Civilisation needs more than the law to hold it together. You see, all mankind are not equally willing to accept as divine justice what is called human law.
 John Buchan
I once played the chief part in a rather exciting business without ever once budging from London . And the joke of it was that the man who went out to look for adventure only saw a bit of the game, and I who sat in my chambers saw it all and pulled the strings. 'They also serve who only stand and wait,' you know.
 John Buchan
The world was arrogant and self-satisfied, but behind all this confidence there was an uneasy sense of impending disaster. The old creeds, both religious and political, were largely in the process of dissolution, but we did not realise the fact, and therefore did not look for new foundations.
 John Buchan
Fortunately for mankind the brain in a life of action turns more to the matter in hand than to conjuring up the chances of the future.
 John Buchan