Christianity is founded upon God’s Law. Capitalism is based on the secular aspects of God’s Law. Socialism is based on the direct violation of two Commandments (coveting and theft), and to function a socialist economy must continually lie.
In short, socialism is antithetical to Christianity.
Liberalism is the belief that the truth is malleable and subject to ideology. In order to make their schemes work, liberals often look to covet and steal the assets and incomes of others. By its very nature, it too is antithetical to God’s Law and thus to Christianity.
Correct. I would add that God considers man a free moral agent. Man is free to make his own choices, even to the point of accepting Him as his god or rejecting him. I think the most fundamental difference in Christianity and Socialism/Marxism is that Christianity emphasizes man as a free moral agent; the latter seeks to severely limit man's freedom. Islam restricts freedom as well.