Ptobably the most famous one...
Muhammad/Allah 5:32 "Because of that, We decreed upon the Children of Israel that whoever kills a soul unless for a soul or for corruption [done] in the land - it is as if he had slain mankind entirely. And whoever saves one - it is as if he had saved mankind entirely. And our messengers had certainly come to them with clear proofs. Then indeed many of them, [even] after that, throughout the land, were transgressors."
This is from the Talmud that Muhammad would learned having a sit down with a local Rabbi. Not from the Hebrew Scriptures but another Rabbi's commentary on the Scriptures. Muhammad/Allah did not know which sayings and teachings were scripture or not.
In other words this would be like Joseph Smith quoting St. Francis instead of the New Testament for Jesus' teachings.
First of all, if you compare those stories mentioned in the Qur'an and the Bible there are significant differences. For example, in the story of Adam and Eve, Qur'an doesn't just blame Eve for eating the fruit - it blames them both equally but the Bible puts the blame on Eve. So it really doesn't add up that you copy the inaccurate and inconsistent material that doesn't make sense from one source(The Bible) and then present the consistent, accurate and reasonable one(in the Qur'an).
Also, in this regard, Dr. Jamal Badawi's statements are worth noting. He says: It would be highly imaginary to say that through his occasional chats with Jews and Christians, while busy with his caravan, Muhammad, learned enough about either or both religions to formulate a new powerful and viable religion, a task that defies the collective efforts of scholars for centuries. as is the case for Christianity and Judaism.
Furthermore, the above assertion raises a number of questions. Dr. Jamal Badawi puts forth the following six questions:
1. Why is it, that in spite of the abundance of historical material on the life of Prophet Muhammad, and in spite of the extensive research on his life for centuries by his critics, why was it not possible to discover the mysterious teacher who allegedly taught Muhammad, , all that he learned?
2. It is known that Muhammad, was opposed, ridiculed and persecuted for nearly thirteen years by his own contemporaries. Was it not possible for his enemies to prove to the masses that Prophet Muhammad's, claim of revelation was sheer fabrication? Was it not possible for them to reveal and name whom they alleged to be the human sources of his teachings? Even some of his adversaries who made this assertion changed their minds later on, and accused him, instead, of magic or of being possessed by evil.
3. Prophet Muhammad, , was raised among his people and every aspect of his life was exposed to them, especially by the openness that characterizes tribal life in the desert. How could his contemporaries, including many of his close relatives who knew him so well, believe in his truthfulness if they had any doubt that he was claiming credit for ideas taught to him by some other teachers, without bothering to give them credit?
4. What kind of teacher might have taught Muhammad, , a coherent and complete religion that changed the face of history? Why did he or they (if any) not speak against the alleged student who continued learning from them, while ignoring them and claiming some other Divine source for his teachings?
5. How could many Jews and Christians amongst his contemporaries become Muslims and believe in his truthfulness, if they knew that he was copying from their scriptures or learning from their priests or rabbis?
6. It is known that some of the Quranic revelations came to Prophet Muhammad, , in the presence of people. The Quran was revealed during the span of 23 years. If the Prophet, , had a teacher, where was he? How could he, , have hidden the teacher for so long? On the other hand, how could Prophet Muhammad, , who was constantly surrounded by followers, be able to make frequent secret visits to that mysterious teacher or teachers for 23 years without being caught even once?
So it is quite clear that Qur'an could not have been copied from any earlier sources but rather divinely revealed.