St. Peter never played baseball. Nevertheless, "Three strikes and you’re out!" seems to be the model he had in mind when he asked Jesus about forgiveness. Like we’re often tempted to do, he assumed that there’s a limit to the forgiveness we can reasonably be expected to give, be it once, three times, or seven times. Jesus understood this. That’s why he stressed that those who follow him are to forgive "seventy-seven times." In other words, without limit.
Jesus doesn’t say that we need to condone what was done to us, deny our pain in being hurt, or trust the person who harmed us. However, he does call us to make the decision to forgive, and free ourselves from resentment and the desire for revenge.
When we refuse to forgive, we contribute to the world’s sorrow (and there’s enough of that already); we demonize the person who wronged us (and that’s unfair to them); and we deny ourselves the gift of God’s forgiveness (which is foolishness to us).
Forgiveness is indeed hard, but Jesus shows us the way, and helps us to do it. After all, he doesn’t call us to give to others, anything he’s not first prepared to give to us.
(My book of daily meditations for Lent is now available from Ave Maria Press:https://www.avemariapress.com/product/1-59471-363-4/The-Living-Gospel-Daily-Devotions-for-Lent-2013/ It is available also at Amazon: http://www.amazon.com/Daily-Devotions-Lent-Living-Gospel/dp/1594713634/ref=sr_1_1?ie=UTF8&qid=1335995419&sr=8-1 )