Both Judaism and Islam, like all great traditions, have developed and expanded the insights of their primary sacred text. The questioner remarks that as a Muslim, he "...is a purist. I follow the Quran and ONLY the Quran." But true literalism is impossible. Were it possible, it would ensure extinction.
Literalism is impossible because any single sentence in the world, however seemingly unambiguous, will be interpreted differently by different minds. "Thou shalt not kill" (or, more properly translated, murder) seems pretty unambiguous. But does it apply to war? Can one bomb a military base knowing that civilians nearby will be killed? Is it murder to kill someone who is torturing you, but will not kill you? Is it murder to take a breathing tube from someone whose brain wave is flat but whose heart is still beating? How certain does one have to be to impose capital punishment without it being considered murder? These questions are not clearly answered by text alone.
Judaism is a tradition of interpretation. Indeed, the one group in the history of Judaism that sought to follow only the text of the Torah, called the Karaites, died out (save a small remnant) in the Middle Ages. Founded by Anan (d. about 800 CE), the Karaites tried to live by the laws of the Torah alone but even they found that it is indeed impossible to follow the Torah without some interpretation. They soon introduced the ideas of "speculation" or "analogy" because they found the Torah text inadequate to all the situations of life.
Though one may believe himself a follower of the letter of a sacred text, I suspect if I questioned any believer carefully enough, we would discover that he is enmeshed in many interpretations. It is an inevitable process of growth and life. The Torah says we should not perform "melachah" on Shabbat (Exodus 20:10, Leviticus 23:3) -- and then does not define melachah. The Rabbis had to determine based on the text and their own wisdom, what melachah meant. (They determined it to be work or other purposeful interactions with nature that were prohibited on Shabbat, such as cooking, plowing, or kindling a fire.)
In classical Jewish thought, the law is divided up into the written law (the bible, or the five books of the Torah) and the Oral Law (the Talmud and other rabbinic writings, along with the many commentaries that have sprung from rabbinic writings). There are those in the Jewish tradition who adhere to a literalistic reading of the oral law. The Talmud comments that every interpretation that a child in the study hall will develop was already revealed to Moses at Sinai. Some take this as a precise statement. For me, as for most modern Jews, this is an expression of the essential integrity of the law. Although the law has changed, grown and developed, the underlying principles and ideas endure. They take different forms as society does, but each is driven by a consciousness of God's will in the world.
This idea of the law as a continuum, something that grows and changes while remaining true to the spirit of the text, is at the heart of Judaism. We are told in the Bible not to transfer a fire on Shabbat. Can one then drive a car? Turn on a light? Open a refrigerator that has a light in it, even though it won't be opened with the intention of turning on the light, but rather to get food out of it? These are not questions that can be answered without learning, sensitivity, and a fidelity to the historical growth of the law.
More than that, from my point of view, there are assumptions the Torah makes which we no longer share. The Torah is predicated on a social structure that is quite different from our own. In that social structure, slavery was accepted. (Even by slaves. In the writings of the great slave/philosopher Epictetus there is no comment on the essential immorality of slavery. In the Torah, non-Israelite slaves are clearly consigned to a miserable life.) The position of women was quite different from our own day. Knowledge of the world, both scientific and humanistic, was so radically different that to assume a static tradition is to assure morbidity. All living is growth; all growth implies change. That which does not change, dies.
All of God's gifts are given for a purpose. God gave us minds with which to reason, to imagine, to understand, to create. Dare we stultify those minds by a fruitless attempt at robotic obedience -- an attempt doomed to fail? Instead we should assume that God's word is a foundation, a launching pad, and a path; it will enable human beings to create as well, for we are partners with God in the great enterprise of sanctification.