1
general::
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]
American Heritage Idioms
2
general::
Phrase(s): keep body and soul together
Fig. to manage to keep existing, especially when one has very little money. (Compare this with keep the wolf from the door.) • We hardly had enough to keep body and soul together. • I don’t earn enough money to keep body and soul together.
McGrawhill's American Idioms And Phrasal Verbs