Definition & Meaning of "take a look in the mirror"

What is the origin of the idiom "take a look in the mirror" and when to use it?

The origin of the idiom "take a look in the mirror" is not rooted in a specific historical reference, but it draws upon the literal act of looking at oneself in a mirror as a metaphor for self-reflection. Mirrors have long been used as tools for self-assessment, allowing individuals to see their own reflection and gain a visual representation of themselves and this expression's usage captures just that, but in the case of self-evaluation.