What does the title ';Of Mice and Men'; mean?

In addition, from what poem, by what author does Steinbeck take the title?What does the title ';Of Mice and Men'; mean?
The meaning of the novel’s title serves as a comparison between strong people and weak people. The mice refer to the weak characters such as Lennie, Candy, Curley’s wife, and Crooks. The men refer to the strong characters like Slim and George. Steinbeck’s title comes from the poem by Robert Burns’ “To a Mouse”.