Also, gird up one's loins. Prepare oneself for action, as in I'm girding up my loins for that crucial interview. This expression comes from the Bible (Proverbs 31:17) and originally alluded to tucking up the traditional long robe into a girdle (that is, a belt) so it will not hamper physical activity. [c. 1600]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.