Ch. 30, v. 13: "Machatzis hashekel" – The first Mishnah in Shkolim says that on the first of the month of Ador there is an announcement made to give the half-shekel and to be careful to avoid "klayim." This is a prohibition against planting certain things together. The half-shekel teaches us that each of us is incomplete, and requires unity with another person to be complete. On the other hand, it is very important to not join with a wicked person. This is why at the same time that we announce the half-shekel we also announce the prohibition of "klayim." We are not to unite with just anybody. (Kol Aryeh)
Ch. 30, v. 15: "He'oshir lo yarbeh v'hadal lo yamit" – It is the nature of a wealthy person to blow up and maximize his donation. It is likewise the nature of the poor recipient to minimize what he has received. Our verse teaches that the donor should not aggrandize himself because of his charity and that the poor man should not minimize the kind act that was done to him. (Rabbi Meir of Premishlan)
Ch. 30, v. 35: "K'to'res" – The gemara Arochin 16a and Z'vochim 88b says that the burning of "k'to'res" incense offers atonement for loshon hora. Symbolically, loshon hora pollutes and putrefies the environment, bringing much ill will and the like. Incense, on the other hand, freshens and scents the environment. (To'afos HoRi"m)
Ch. 31, v. 14: "Ushmartem es haShabbos" – The Holy Zohar writes that Shabbos is one of the Names of Hashem. The Gemara Shabbos 12a says that one should constantly touch his tefillin so that he will constantly be aware of his wearing them. The Gemara then says that one should also touch the garment that he will wear on Shabbos, i.e. check his pockets to make sure that he has no item in the pocket as he might walk from domain to domain with the object on Shabbos, transgressing the act of carrying from domain to domain. Rabbi Yoseif concludes "hil'ch'sa rabasi l'Shabbos," this is a great halacha for Shabbos. Since our verse says that we should safeguard Shabbos, perhaps we can say that Rabbi Yoseif was making a "kal vochomer" from tefillin to Shabbos. If one has to continually be aware of his holy tefillin, which contain the Name of Hashem 42 times, "hil'ch'sa rabasi," all the more so, should he be consciously aware of the sanctity of Shabbos, as Shabbos is itself the Name of Hashem. (Nirreh li)
