'לא תוסיפו וגו, “do not add, etc.;” G–d implies that anyone adding to the words of the Torah,-however well meaning he may be,-will in fact detract from the value of the Torah. [If G–d is perfect, something that every believing Jew accepts as axiomatic, any addition to or deletion from His Torah would make it, ergo Him, imperfect. Ed.] For instance, when the Torah decreed 4 strings of tzitzit for the corners of a four-cornered garment, adding a fifth string would not only not make it holier, but would make it useless, and anyone reciting a benediction over such a tallit would desecrate the holy name of G–d by pronouncing such a benediction. The same reasoning applies to sitting in a sukkah for an extra day or adding another a fifth species to a lulav.