Sit down, relax, as in I wish you'd take some time and take the load off. A shortening of take the load off one's feet, this colloquial phrase dates from about 1940. It is sometimes put as take a load off.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.