You are right about you talked. Life is a and what goes down comes up and vice versa. No condition is permanent on this earth and as long as we are in the world it is good to do good to anybody around us because we did not know what could be the out come of that person in future

God has created this world for us to live and the same time created us to be judged by our action to another human fellow.
Some people are very wicked in their life, they have bad character and negative thoughts always totally towards their fellow human being they forget that life is reciprocal. i.e what ever you do will certainly come to you and rewards

Yes, Life is like earth and, anything you do in this world yo will have it back. That is how God do it and that means what goes around will surely come round. This is telling us that we must do good all the times because there is the reward for whatever we do on earth either good or bad.