take a stand on

(verb) to have a strong opinion about something and not change it

Example Sentences:

A: What did you do about your teenage son?
B: I decided that I had to take a stand on his bad behaviour. I told him he couldn’t leave the house until he improved his school marks.

Politicians are always taking a stand on important topics, and then changing their minds.

Karl knew that the most important moment in his life was when he took a stand on the environment and decided to live a more green life.

Similar idioms:

1. stand out
2. have a green thumb
3. give someone the green light
4. at a crossroads