muster up
verb1
Look within oneself to summon a particular positive quality, such as strength, energy or courage.
- I mustered up all my remaining willpower.
- Nobody save myself so much as turned to look after him; nor, it grieves me to confess, could even I contrive to muster up any tolerable interest, even by all that the warlike spirit, formerly manifested within that now decrepit shape, had wrought upon our globe.1846, Nathaniel Hawthorne, “P.'s Correspondence”, in Mosses from an Old Manse: