What are the differences between communism and socialism according to Marx and Engels?

Question

Please use this source for citations and everything else: https://avalon.law.yale.edu/19th_century/manfour.asp

Answer 1

According to Marx and Engels, communism has a clear end goal of achieving the "enforcement of the monetary interests of the working class." Communists fundamentally believe that the achievement of this end goal can be attained only by "the forcible overthrow of all existing social conditions." Socialist movements, on the other hand, are much more nuanced; these movements have various end goals, many of which do not include complete and total communist rule. For example, Marx and Engels write that they support the Radicals of France, despite this party consisting of many "radical bourgeois." Communists also support the bourgeoise of Germany "whenever it acts in a revolutionary way, against the absolute monarchy, the feudal squirearchy, and the petty bourgeoise."

Why would communists support bourgeoise-backed socialist movements, despite their radically open disdain for the bourgeois class? It is due to the fact that socialism is a transitioning phase into communism. Marx and Engels claim that these socialist movements in Poland, France, Germany, and elsewhere are "the future" of the communist movement. Of the socialist movement in Germany, Marx and Engels write "the bourgeois revolution in Germany will be but a prelude to an immediately following proletarian revolution."

What's the bottom line?

Communists believe in the uprooting of existing social and political order, and the complete control of monetary power and property in the hands of the working classes. Socialist movements, in the eyes of Marx and Engels, represent a critical step that a society takes in its transition into a communist society, where existing political and social conditions are disrupted and uprooted. Marx and Engels justify supporting socialist movements, despite having philosophical differences, because the success of such movements represent a critical step on a nation's journey to become a communist state.

Source: https://avalon.law.yale.edu/19th_century/manfour.asp