Before we go on to that, must mention that the Chief Executive's speechwriters need to be a bit more on the ball in terms of quoting Scripture. At one point, the new president said, in his National Prayer Breakfast speech this morning, "The Torah commands, "That which is hateful to you, do not do to your fellow." "The reference is b. Shabbat 31a. The positive formulation, "Love your neighbor as yourself" does appear in the Torah in Leviticus 19:18.
That is not in the Torah, aka the Old Testament. It's from the Talmud, specifically a quote from Rabbi Hillel in the book Talmud Shabbos. (The Talmud, a 20-volume biblical commentary, was compiled by Jewish sages in second-century AD Babylon.)
Ms. Duin makes her own error in her comments. The Babylonian Talmud was compiled (based on lots of earlier material) in (roughly) the sixth century, not the second.
UPDATE (7 September): Reader Aryeh Amihay e-mails in defense of the President:
In relation to your post on President Obama’s misattributed Talmud quote I wanted to add that the story of Hillel as it appears in tractate Shabbat, has Hillel stating that “What is hateful to you, do not to your neighbour. that is the whole Torah, while the rest is the commentary thereof; go and learn it.” In other words, according to Hillel himself this is what the Torah commands, rendering the president’s statement true (he did not say he was quoting from the Torah, only that this was what the Torah commands).