I'm in Romans chapter 3. It's right after the classic verse, "we've all sinned, we've all fallen short...". The only 'righteousness' I have...the only reason I am free is because of this 'undeserved kindness' that God has shown me.
It's easy to be kind to those who deserve it. It's 'a whole notha level' to be kind to those who don't deserve it.
I'm glad that I don't get what I deserve, aren't you?
So, when your waitress is having a terrible day, give her a bigger than usual tip, not less. That's Romans 3:24.