gird up one's loins

gird (up) one's loins ( to get ready, especially for hard work, fro something requiring readiness, strength, or endurance; to prepare oneself for sth difficult or demanding; to summon up one's inner resources in preparation for action) — поэт. препоясать чресла {библ.; поэт.},|| собраться с силами,

.... Well, I guess I had better gird up my loins and go to work. (thefreedictionary.com)
.... He girded his loins to face his competitor.

Related vocabulary:
eat one's Wheaties,
steel oneself,
shape up,
suck it up