To gird up is to prepare yourself for hard effort. Gird up for the week ahead.
It comes from tucking up a long robe so you could move, which is exactly what girding meant. To gird up is deliberately old-fashioned and half humorous in modern use.
1phrasegird upTo prepare yourself for hard effort.
“He had to gird up before every meeting with that committee.”
gird up is a phrase.
Practised in A Song of Ice and Fire