This shows the Prussian Leibgarde (guards) standing against the Austrian heavy cavalry at the Battle of Kolin. This was the first big Prussian defeat in the Seven Years War, and the action showed here took place after every single Prussian disorganised attack on the far superior numbers of the Imperials had failed. At some point, the retreat of the army was called but frightened of disaster as the Austrian went in pursuit (a thing rarely done by commanders during this war).
That's the point where Frederick the Great went to find his guardsmen, waiting undecisive and frightened, and had these famous words: "Ihr Racker, wollt ihr ewig leben?", translating "You rascals, do you want to live forever?". For some it shows how cynical and cold Frederick would have been, but in the context, the words would have been highly rousing for these Prussians. The sentence is to be understood in a bold way, flattering prussian courage and self-abnegation, meaning everyone has to die someday, which bett