He was oppressed, and he was afflicted,
yet he opened not his mouth;
like a lamb that is led to the slaughter,
and like a sheep that before its shearers is silent,
so he opened not his mouth.
In I Peter 2:21-25, Peter uses this as an example of how we are to behave and submit, even in times of suffering. But Peter adds some insight into the way that Christ was able to "...answer not a word." He tells us that, "When he was reviled, he did not revile in return; when he suffered, he did not threaten, but continued entrusting himself to him who judges justly."
Refraining from retaliation does not mean that you are a doormat. Sure, you may look like a sheep going to slaughter, but you do it knowing that you are entrusting yourself to THE Judge... The Judge who judges justly.