A thought provoking concession

I just had a wonderful conversation about God’s justice with one of my co workers who is a Muslim. His point is that I can not forgive and forget a wrong when in Islam I have the option from God to seek justice on my own. I said since you have the option why not allow God to take on the battle since Justice is always from God he is the only ONE who is Just. The only reason you would rather place justice into your own hands is that you are able. If you were a child or a older man who is incapable to fight you would allow your faith in God fight your battle, he said I never thought of it that way.