You are getting an essay.... a ramble.. I hope you don't mind....
Humans think that they are the only ones who possess Kindness, but they aren't.
Kindness, permeates all of Creation; it is Empathetic, Intuitive, as well as the foundation of all "humane" behaviors.
I'll say again....Humane Behaviors.
Kindness is much more than gentle submission. It has a Nobility to it. Science tell us that aggression for access to procreation and hunting grounds drove the engines of Evolution. Watching how a female bird chooses a mate puts the lie to that. She makes the choice, not the male. Mammals are an aberration, a serious one.
We can learn Kindness, and enrich it within ourselves, by practicing it. Some people learn, with a shock, that they have the roots of it buried in their DNA, and they can change almost instantly when moved to it.
I've seen this transformation in children, and in adults. It's like every atom in their body relaxes and they become at Peace. So, does Kindness have a component of Peace in it? Yes, I think Kindness is Inner Peace. Kindness is what shows on the outside. It's an expression of Inner Peace.
It didn't take long for the aggressive among Humans to learn that they can use other people's kindness against them. So, Kindness also has a component of apparent subservience in their eyes. And, so it became something that they aggressively took advantage of. And thus, the Rewards in Heaven theories....
However, Kindness on Earth is Heaven on Earth.