Supergirl, Season 4

Kara:
You were right, about the crimes. They were motivated by hate. And there's a web of people...

J'onn:
Now that you know what's happening, you can fight it, Kara.

Kara:
But I need your help. They're going to attack the alien summit. Help me keep it safe, and then help me take on the rest of this movement, because it is bigger than anything I have ever fought. The people involved in it are like the people I save every day. A villain, I know how to stop, but these people...

J'onn:
I'm sorry, but I cannot fight with you. Not this time.

Kara:
But... but you have to. You were the first person to see this. You... who yelled at me to open my eyes, so how can you not join me now?

J'onn:
Because it's no longer my path to fight. When my father passed, he gave me a message: live as H'ronmeer taught and promote peace. I cannot do that whilst wielding a sword. I will help those in need, and I will be a voice for change like Dr. Vose. I will support you, Kara, but I cannot join your battle. I'm sorry.