How do you respond to a bully? What sources of power do you call upon? Is being kind weak and cowardly?
You are brave because you are vulnerable. You are strong enough to be vulnerable. Which is more brave? Stopping a bully by beating them up, or facing a bully without resorting to violence? Being kind means you expose yourself to possible harm-–be it physical, emotional, economic, reputational, temporal, and so on. You take the risk. You refuse to use the ways of the bully in response to the bully. You also don't run away from conflict with a bully unless it is just to buy some time, to retreat temporarily, in order to organize, consider your options, and find your sources of power. You don’t passively submit to the bully.
The classic advice is to stand up to a bully. Being relational means you don’t stand up to a bully by returning the bully’s violence with violence, intimidation with intimidation, lies with lies. You sit down with a bully-–if possible. If need be, you wear them out with dialogue – relentless engagement. When you are afraid or angry, that might be the hardest and bravest thing you ever do.