This statement is attributed to the German anti-Nazi activist, Pastor Martin Niemöller:

First they came for the Jews
and I did not speak out — because I was not a Jew. 

Then they came for the Communists 
and I did not speak out — because I was not a Communist. 

Then they came for the Trade Unionists
and I did not speak out — because I was not a Trade Unionist. 

Then they came for me —
and by then there was no one left to speak out for me.