[take|pick] up the cudgels

to show one's support of someone or something by defending them at any cost

The idiom "take up the cudgels" originated in the late 16th century and is derived from the literal act of wielding cudgels as weapons. Cudgels were short, thick sticks used in combat during that time. In a figurative sense, this expression is often used when discussing debates, arguments, or contentious issues where individuals passionately advocate for their beliefs.

When faced with criticism, she quickly picked up the cudgels, passionately defending her artistic vision.
The activist took up the cudgels on behalf of marginalized communities, tirelessly advocating for equal rights and social justice.
During the heated debate, he took up the cudgels for his team, passionately arguing their case to secure victory.
The lawyer picked up the cudgels for her client, fiercely defending their innocence in the courtroom.
Seeing the unfair treatment, he took up the cudgels and spoke out against discrimination, demanding change.