stand one's ground
Also, hold one's ground; stand fast. Be firm or unyielding, as in You've got to respect him for standing his ground when all the others disagree, or I'm going to hold my ground on this issue, or No matter how he votes, I'm standing fast. This idiom, dating from the early 1600s, originally was applied to an army holding its territory against the enemy, but was being used figuratively as well by the end of the 1600s.