It's a matter of principle.

Meaning

It's a question of fundamental beliefs and values.

Examples

• John: I cannot compromise on this; <b>it's a matter of principle</b>.
• Alice: I respect your stance; however, we need a practical solution.
• John: My values are non-negotiable; <b>it's a matter of principle</b>.
• Alice: Perhaps we can find a compromise that respects your principles.