1) HALACHAH: PERSONAL HYGIENE
QUESTION: The Gemara records various reasons why a person should clean himself in the bathroom with his left hand, and not with his right hand. The right hand is considered important and deserving of respect, for five reasons:
First, the Torah was given with the "right hand" of Hash-m, as the verse says (Devarim 33:2).
Second, one eats with his right hand.
Third, one wraps the straps of his Tefilin with his right hand.
Fourth, one shows the notes for reading the Torah with his right hand.
Fifth, the right hand is used for writing.
With what hand should a left-handed person clean himself? Since a left-handed person eats with his left hand, wraps the Tefilin straps with his left hand, shows the notes for reading the Torah with his left hand, and writes with his left hand, should he clean himself in the bathroom with his right hand? According to the last four reasons in the Gemara, a left-handed person may not clean himself with his left hand, but should use his right hand. Those reasons are based on the idea that the hand that is used for important and respectable acts should not be used for a lowly act. However, according to the first reason, even a left-handed person should not clean himself with his right hand, because the Torah was given with the "right hand" of Hash-m! (Perhaps this is why that reason is mentioned first even though it was given by Rava, who lived later than some of the Amora'im who give the other reasons (Y. Tavin).)
ANSWER: The SHULCHAN ARUCH (OC 3:10) rules that one should not clean himself with his right hand. Regarding a left-handed person, the TAZ writes that the Halachah follows the majority of reasons in the Gemara, and therefore a left-handed person should use his right hand. For this reason, both RABEINU CHANANEL and the ME'IRI do not mention the reason of Rava.
2) COUNTING THE JEWISH PEOPLE
QUESTION: The Gemara teaches that it is forbidden to count the Jewish people directly. They may be counted only indirectly, such as through donations of half-Shekalim, as derived from the verse (Shemos 30:12). The Gemara relates that David ha'Melech attempted to count the Jewish people directly, and he was punished for this (as related in Shmuel II, ch. 24).
How could David ha'Melech make such a mistake and violate an explicit prohibition in the Torah?
(a) The RAMBAN (Shemos 30:12) explains that David ha'Melech thought that the prohibition to count Jews directly applied only in the Midbar, when there was an additional need for the coins given for the census. (The Adanim for the Mishkan were made from the coins.) He mistakenly understood that it was not a commandment that was binding for all generations.
(b) The MIZRACHI (ibid.) explains that David ha'Melech understood that the coins in the Midbar were not given as a means by which to count the Jewish people. Rather, he thought that a regular census indeed could be conducted, after which a half-Shekel had to be given as a Kofer Nefesh in order to avoid the plague that would otherwise follow due to the Ayin ha'Ra of the count.
(c) The BE'ER SHEVA (Tamid 28a) explains that Hash-m caused David ha'Melech to make this mistake as a punishment for something else that he had done. The Gemara here relates that Hash-m told David ha'Melech, "You said that I 'persuade' people to sin? I will punish you by having you forget something that even children know...." There was a Divine decree for David ha'Melech to forget the verse this one time.