Frederic Bastiat was one of the first to make the connection:
"We are confronted with still another cause of inequality, more active perhaps than all the others: the war against capital. The proletariat can be freed in only one way, by an increase in capital. When capital increases more rapidly than the population, two unfailing effects follow, both of which contribute toward improving the lot of the worker: lower-priced products and higher wages. But, for capital to increase, it requires above all security. If it is afraid, it hides, secludes itself, and is dissipated and destroyed. It is then that labor is unemployed and is offered at the lowest price. The greatest of all evils for the working class is, then, to let itself be drawn by flatterers into a war against capital as absurd as it is disastrous. This is a constant threat of plunder, worse than plunder itself." Frederic Bastiat (in Property and Plunder)
In a piece in Forbes about inequality I list list five factors that lead to unjust inequality:
"It was not nature that determined that Argentina, after becoming one of the 10 wealthiest and freest countries of the world in the 1940’s, would begin a steady descent. It was not nature that made Chile and South Korea leave Argentina far behind in economic development. It was the actions of humans, acting individually or in groups, which made the laws helping to enhance or curtail the exercise of freedom in the economic sphere."