Gen 30:33a "So my righteousness will answer for me in time to come..."
After making Laban unbelievably rich and successful, Jacob was getting tired of serving his father-in-law, so he basically asked him to allow him to leave with his family. Laban wanted to pay him for the work that he had done so they made a deal. Jacob would get the brown, spotted and striped livestock and Laban would keep all the others. That way, if an argument arose in the future as to who owned a certain sheep or goat, all they had to do was look at whether it was striped or spotted and it would be clear, because of genetics, that it was owned by Jacob.
That is where this verse comes in. "In time to come, when there is a question, my righteousness will answer for me. When you doubt whether certain flocks are mine, all you have to do is look at them and you will tell that I have not cheated you. I will be true. I will be honorable. I will not cheat. I will only claim what is rightfully mine." In other words: "In the future you will be able to tell that I did what was right."
This is the law of sowing and reaping. This is the law of what goes around comes around. This is the law of paying it forward. So many times we are tempted to take shortcuts, to cheat just a little, to take something that is not rightfully ours, to tell a little white lie. This was not Jacob. He was not going to take a shortcut, he was not going to cheat, he was not going take any of Laban's flocks and he was not going to lie about it. He was going to do what was right and true and honorable and the result was going to be shown in the future through the fruit of his life.
The point: If I am ever questioned about my words or my actions or my motives, and if I do what is right and I live a life that is clean before God then I can say with Jacob: "My righteousness will answer for me in time to come."