First of all Deuteronomy 17 is instruction to the judges of Israel. Unlike Islam where its followers just kill people indiscriminately. The judges also needed the testimony of two or three witnesses. Also, the objective God had in choosing Israel was to preserve the knowledge and worship of the one true God Jehovah! Islam is the "moon god religion." Even though Islam wasn't around back then (thanks be to God) the Judges of Israel were told to bring moon worshipers and the like to justice. There's very little justice in the lawless religion of Islam. Muslim's simply take things into their own hands like they did on 911. Another difference is that the judges were commanded to make sure that any Israelites who went after idolatry should be investigated, and if found guilty, go before a judge, have the testimony of at least 2-3 witnesses, and then if found guilty, be put to death. Unlike Islam where "everyone who is a non Muslim" is an infidel and Muslims are encouraged to kill them "wherever they find them." No judges, no trial, no witnesses, no justice! And the witnesses had to be so certain of what they saw that they had to be willing to initiate the actual execution. This puts the words of Jesus regarding the woman taken in adultery in John 8 in perspective. John 8:7 He who is without sin among you, let him throw a stone at her first. Jesus asked for the official witness to step forward and identify themselves on record as having witnessed this act of adultery, yet the mob was hypocritical enough to bring the woman and not the man. And if you read further into chapter 14 you'll see that there was an appeal process! These were higher courts where cases were taken beyond the local judges to the priests and the Levites who were understood to be wiser judges because of their knowledge of God's Word Another thing is that the book of Deuteronomy is under the Old Testament law. Since Jesus Christ has come, died and was crucified, and risen the third day, Israel is no longer under that law! And neither are we as Christians.