Therefore we in the west must not confuse what is a barbaric practice with the so called "peace loving" religion of Islam.
From Planck's Constant blog
Hadith Sahi Muslim No. 4206,
A woman came to the prophet and asked for purification by seeking punishment. He told her to go away and seek God’s forgiveness. She persisted four times and admitted she was pregnant. He told her to wait until she had given birth.
Then he said that the Muslim community should wait until she had weaned her child. When the day arrived for the child to take solid food, Muhammad handed the child over to the community. And when he had given command over her and she was put in a hole up to her breast, he ordered the people to stone her. Khalid b. al-Walid came forward with a stone which he threw at her head, and when the blood spurted on her face he cursed her.
Now Muslim apologists will tell you that in order to sanction killing, it must be done through a binding verdict issued by an authoritative law court. Individual Muslims have no authority either to judge cases or pass judgments and thus, Honor Killings by individuals are prohibited.
But what is a Muslim father to do who lives in Canada or the US or Germany where there is no Shariah, where no court of law will issue a verdict of death against his daughter or wife for being lewd?