If this was all we knew about Jacob then it might be easier to feel sorry for him. I know that I have a hard time seeing people being cheated and unfairly treated. But it is a bit of a different story when the person being cheated is dishonest. Who doesn't like to see someone get their comeuppance?
"Now Jacob heard that the sons of Laban were saying, 'Jacob has taken all that was our father’s, and from what was our father’s he has gained all this wealth.' And Jacob saw that Laban did not regard him with favor as before. Then the Lord said to Jacob, 'Return to the land of your fathers and to your kindred, and I will be with you.'
"So Jacob sent and called Rachel and Leah into the field where his flock was and said to them, 'I see that your father does not regard me with favor as he did before. But the God of my father has been with me. You know that I have served your father with all my strength, yet your father has cheated me and changed my wages ten times. But God did not permit him to harm me.'"
Jacob cheated and stole his brother's birthright and blessing so on a certain level it is satisfying to see Jacob get a taste of his own medicine. Hence the saying: "You reap what you sow."
But does Jacob's cheating behavior make it ok for Laban to cheat Jacob?
I would guess that most people would agree that it wasn't right for Laban to cheat Jacob regardless of what Jacob had done in the past. So if it isn't right for Laban to cheat Jacob then is it still right for us to take satisfaction in Jacob getting a taste of his own medicine? Can we still root for Jacob being cheated when we are condemning the person doing the cheating? Not if we want to be consistent.
My guess is that we aren't really rooting for Laban to cheat Jacob when we take satisfaction in Jacob getting a taste of his own medicine. Rather what is happening is that we have an innate desire to see justice done. The problem is that we can often seek to see justice done even when it comes in the form of an act of injustice. Seeking the right result through the wrong means is still wrong. There is a right way and a wrong way to seek justice. It is why vigilantism is illegal.
This isn't to say that all forms of punishment are wrong. We have a justice system (as broken as it may seem at times) for a reason. What we need to be careful about is when we start to take satisfaction in seeing unjust forms of justice take place. When we do we are promoting and justifying injustice.
Scripture quotations are from The Holy Bible, English Standard Version® (ESV®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved.