Sharia Law was introduced after the Qur’an was published, and therefore it is not the final authority in Islamic law, yet it is treated as much. Yet, within Sharia Law, there are five schools of thought regarding the interpretation of the Law and therefore its application. It all depends also on whether the interpretation comes from Sunnis or Shiites, and then within those two main groups there are variations as to high strict the interpretation is and whether it is to the benefit of a country to twist it when it deals with the western world.
I therefore would contend that Muslims, especially their leaders should turn to the Qur’an only for their ‘rules’ and not the Sharia as this is very much made up by men who interpret the Qur’an in many different ways. We must remember a lot of Sunnis cannot stand the Shiites and vice versa, so they are often trying to outdo each other as to high strict they can make it. Hence, the rise of the Islamic State, Taliban and others.
If they did just rely on the Qur’an, I am sure we would not get so much of the extremism in certain sections of the Islamic community. Yet, some of the Qur’an does not bode well for Christians, hence most persecution comes from Muslim countries, despite many of them having signed UN human rights covenants and their constitutions have enshrined freedom of religion which includes freedom to change religion.
Despite that, Christians are still called to love their persecutors and tell them about the Good News of the Gospel of the Kingdom of God.
For more information on Sharia law, have a look at the following link – https://en.wikipedia.org/wiki/Sharia#Historical_origins