On this day...

Today in 1944, the family of Corrie Ten Boom was betrayed to the Nazis by an informant...

... in spite of a two day search, the gestapo never found the six people in the ten Boom's hiding place.
Casper ten Boom, Corrie's father, died in prison ten days after his arrest. Corrie and Betsie were transferred to the Ravensbruck death camp, where Betsie later died Christmas day. The Jews behind Corrie's bookcase were freed, hidden again, and ultimately survived the Holocaust.
In June 1945, four months after her release from Ravensbruck, Corrie forced herself to write a letter that pained her greatly. It was to the Dutch stranger who had asked for help that day in the shop and whom Corrie now realized had betrayed her family to the Nazis.
I heard that most probably you are the one who betrayed me. I went through ten months of concentration camp. My fater dies...and my sister died in prison.
The harm you planned was turned into good for me by God. I came nearer to Him. I have prayed for you , that the Lord may accept you if you will repent. I have forgiven you everything. God will also forgive you everything if you ask Him.
Rescuing dozens of Jews in Holland turned out to be the beginning of her life's work. God led her first to forgive her betrayer, then sent her out at age fifty-four with message to the post-war world.

from The One Year Book of Christian History