Insist on doing
Definition 1 of 1
Pro Tip 1/3Persuasive persistence
Used when someone won't easily give up, showing determination to have things a certain way. 
He insists on doing the presentation himself, despite the team's offer to help.
Pro Tip 2/3Slight annoyance
May imply that someone's determination is causing irritation or inconvenience to others. 
She always insists on doing everything her way, which frustrates her coworkers.
Pro Tip 3/3Moral conviction
Can reflect a deep belief in personal principles or values guiding someone's actions. 
He insists on doing the right thing, even when it's not the easiest option.