Answer:
A good deed has it's own reward because it is a good deed. If you do something to help someone that makes you feel good about yourself. You don't always need to be rewarded for something you do because the idea that you helped someone in need of help should be enough. If yowalwalijg down the street and see a homeless man and you decide to give him 100 dollars that's a good deed that greatly helped him. you should be satisfied with the idea that you greatly improved someone's day even if it took your money. Let's say you were at school and you saw a kid that looked sad and was sitting alone and you go to talk to him. You don't expect anything form him or anyone your doing that beacsue your kind. That's my reason of why "A good deed has it's own reward.".