the shirt off somebody's back

the shirt off (one's) back

Anything or everything one owns or has to offer. Those contractors will take the shirt off your back if you hire them. I mean, I paid them an exorbitant amount of money, and look at the shoddy work they did! I'm not surprised that Tammy loaned you money—she would give you the shirt off her back if you needed it.
See also: back, off, shirt
Farlex Dictionary of Idioms.

the ˌshirt off somebody’s ˈback

anything that somebody has, including the things they really need themselves, that somebody else takes from them or they are willing to give: He’s the type of person who would give the shirt off his back if he thought it would help.
See also: back, off, shirt
Farlex Partner Idioms Dictionary
See also:
  • the shirt off (one's) back
  • the shirt off back
  • the shirt off your back
  • have the shirt off (one's) back
  • would give (someone) the shirt off (one's) back
  • I see what you mean
  • give (someone) the shirt off (one's) back
  • give the shirt off back
  • give the shirt off one's back
  • button-down