What is the origin of the idiom "stick up for someone or something" and when to use it?

The idiom "stick up for someone or something" finds its origin in the imagery of physically brandishing a stick or weapon in defense. The word "stick" refers to a long, slender object that can be used as a makeshift weapon. The idiom emerged from the literal act of using a stick to protect oneself or others from harm. It is commonly employed in personal relationships, such as friendships or family dynamics, when someone stands up for a loved one in the face of criticism, bullying, or injustice.