Prophets cannot sin?

I was learning about Sa'adyah Gaon 's approach to various Biblical stories and came across this statement (footnote 37 here , bolded by me for emphasis): >S. Stuber, in his article, "מפגשי בראשית – בין אברהם למושלי הארצות", in ספר היובל לרב מרדכי ברויאר (Jeruslaem, 1992): 129-146, **identifies these heretics as the surrounding Muslims. They claimed that this story was a forgery inserted into the Torah, for it is inconceivable that a prophet could lie.** A similar statement is repeated here (bolded by me for emphasis): >Polemical motivations – R. Saadia's full-throated defense of Aharon's actions may be partially motivated by an attempt to counter **Muslim claims that passages in the Torah which portray sins of prophets are forged insertions**. Is it true that Muslims believe that a prophet cannot sin, and that any bible passage that says so must be incorrect/a later insertion? Please provide sources if possible, and thanks in advance!