In life, we all need to be kind to one another. Be it in money, ideas, manner of approach, gift, greetings, anything you know can make another person feel happy. Do it without looking at the tribe, culture or religion, we are all one in the planet earth.
You're in point, sometimes we might know how far our little kind can go. Kind kind doesn't mean when someone is rich or wealthy. We can show kindness in different way, to everyone not just people who can repay our kindness back.