A desire to get even is natural when we are wronged, and it's so easy to follow our instincts and strike back, one way or the other. But through Christ, our hearts have been changed, and we can learned to change our natural responses.
This blogger writes about how Joseph, when placed in a position of power over people who had wrong him, chose to hand out grace, rather than revenge. His decision likely wasn't an easy one, but he chose to honor God by choosing grace.
They didn't deserve it, but then, isn't that what grace is--unmerited favor? Despite their mistreatment of him, Joseph showed mercy and grace...and so should we. After all, haven't we been give grace? Do we deserve it?