Stay alive, support life, as in He earns barely enough to keep body and soul together. This expression alludes to the belief that the soul gives life to the body, which therefore cannot survive without it. Today it most often is applied to earning a living. [Early 1700s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.