The source of this quote is unknown but it rings true.
The Ten "Cannots" of Political Economy:
You cannot bring about prosperity by discouraging thrift.
You cannot strengthen the weak by weakening the strong. You cannot help small men by tearing down big men.
You cannot help the wage-earner by tearing down the wage-payer.
You cannot further the brotherhood of mankind by encouraging class hatred.
You cannot help the poor by destroying the rich.
You cannot establish sound security on borrowed money.
You cannot keep out of trouble by spending more than you earn.
You cannot build character and courage by taking away man's initiative.
You cannot help man permanently by doing for them what they could do and should do for themselves.
Source: Libertarian quotes.