Milton Friedman:

The great movement toward government has not come about as a result of people with evil intentions trying to do evil. The great growth of government has come about because of good people trying to do good. But the method by which they have tried to do good has been basically flawed. They have tried to do good with other people’s money. Doing good with other people’s money has two basic flaws. In the first place, you never spend anybody else’s money as carefully as you spend your own. So a large fraction of that money is inevitably wasted. In the second place, and equally important, you cannot do good with other people’s money unless you first get the money away from them. So that force – sending a policeman to take the money from somebody’s pocket – is fundamentally at the basis of the philosophy of the welfare state.

Thanks to Cafe Hayek.