1) Ch. 19, v. 2: "Zose chukas haTorah asher tzivoh Hashem leimore" This is the statute of the Torah that Hashem commanded thus saying The expression "chukas haTorah" is unusual. We find the Torah saying that this is "chukas haPosach" (Shmos 12:43) or the like, where the Torah says that this is the statute of this or that specific mitzvoh. Our verse seems to indicate that "this is the statute for the whole Torah."
2) Ch. 20, v. 3: "Va'yomru leimore" And they said to thus say Why the double expression?
3) Ch. 20, v. 8: "V'nosan meimov v'hotzeiso lo'hem mayim" And it will give forth its waters and you will extract for them water Why the double expression "n'sinoh" and "hotzo'oh?"
4) Ch. 20, v. 27: "Va'yaas Moshe kaasher tzivoh Hashem l'ei'nei kol ho'eidoh" And Moshe did as Hashem commanded in sight of all the congregation How was this "as Hashem commanded"? In verse 25 Hashem commands Moshe to ascend Hor Hohor with Aharon and Elozor, but without mentioning to do this in the public view.
5) Ch. 20, v. 29: "Va'yivku es Aharon shloshim yom kole beis Yisroel" And all beis Yisroel cried over Aharon for thirty days Rashi (Pirkei d'Rebbi Eliezer ch. #17, Ovos d'Rebbi Noson 12:3) says that because Aharon brought harmony between neighbours and husband and wife, ALL beis Yisroel mourned him. Yalkut Shimoni says that this was not the case with Moshe, where only the men mourned him. Moshe admonished people for their wrongdoing, but Aharon didn't. As well, Aharon brought peace between those who argued. If Aharon's behaviour was so laudable, why didn't Moshe do the same?