"Western Law" is based on Christian values, as found in the Bible, and based on the Old Testament. "Islamic Law" or "Sharia" is based on the Koran, and the same "Old Testament" scriptures with...
Islamic Laws are enshrined in the Holy Quran (Allah's words, as revealed to His last prophet, Muhammad via His archangel Jibril) and the Sunnah (the sayings and traditions of Prophet Muhammad)....
Sharia laws are laws based on the Coran; the holy book of Islam. They are tightly connected with theocracry, in countries such as Iran. But also other Islamic countries use this set of religious laws.