If you look at the history of Marxism and socialism, you will come to an Italian named Gramsci. He devised a plan for the eventual takeover of the Western world by the socialistic/communist economic system. At the time, the communists of the day were frustrated at the West’s ability to withstand their appeals to class warfare as a means of dividing society and bring about the sorts of social change that they always push for. Their conclusion was that Christian teaching and belief was the bulwark of the Western system and its great defence. Before society could be transformed, they realised that it had to be unmoored from its religious foundation. Their project has been largely successful and what you’re seeing now with the Islamic invasion is one of many unintended side effects. If anything Islamist violence helps with remaking the societies of Europe because it provides justification for more invasive government surveillance and more restrictions on the public.

You need not worry about the Christian church. Whenever evil raises its head, God inevitably raises up a standard against it to destroy it. John 16:33 [Jesus is speaking] These things I have spoken to you, so that in Me you may have peace. In the world you have tribulation, but take courage; I have overcome the world.