The Talmud (Shabbat 56a) states "Whomever says (King) David sinned, is mistaken." The Abarbanel (in the section of the book of Samuel dealing with King David’s "sin") writes: "I am one of the mistaken ones." And then proceeds to enumerate at least five transgressions of King David in the affair. Is this acceptable, to just disregard the Talmud?

I reviewed the commentary of the Abarbanel on Shmuel II (Chapter 11) and I did not find that he said the words: " I am one of the mistaken ones." If he indeed said so it is only rhetoric which is characteristic to his time. Nonetheless,he does not disregard the Talmud. The Abarbanel finds the expounding of the Talmud difficult to reconcile with the simple verses in which David himself says "I have sinned." (Shmuel II, 12,13). He therefore chooses a different interpretation which is closer to the "pshat"=the simple understanding of the verse, in his opinion. He then also says that David did full repentance, was punished and was completely forgiven by G-d. Rashi in many places juxtaposes the "pshat" with the "drash" and in fact places his understanding of the "pshat" before the "drash" of the Rabbis in the Talmud. (See for example Rashi Beraishit 37:2) This in no way is disregarding of Chazal. However it is method of commentary employed by many commentators of the Tanach.