It is a mitzva to put up a nice, decorated, aesthetically pleasing sukka, at it is written, “This is my God, and I will glorify Him (ve-anvehu)” (Shemot 15:2), which the Sages expound to mean: “Beautify (hitna’eh) yourself before Him through mitzvot: Make a beautiful (na’ah) sukka, a beautiful (na’eh) lulav…” (Shabbat 133b). The idea of beautifying mitzvot – “hidur mitzva” – applies to all the mitzvot.
In the times of the Sages, they customarily decorated the sukka with colorful tapestries and wall-hangings. They would also hang fruits and nuts – walnuts, peaches, almonds, clusters of grapes, pomegranates, wreaths made of stalks, and glass containers full of wine, oil, and fine flour (Shabbat 22a). Eating from them was forbidden during the festival, since they had been set aside for the mitzva of decorating the sukka. Only one who stipulated before the festival that he could eat them as he wished was permitted to do so (as will be explained in the next section). Nowadays, it is less common to decorate the sukka with food. Rather, we decorate the sukka with paper and plastic chains, paper flowers, pretty pictures, and decorative lights. We also make a point of using nice tablecloths, dishes, and silverware in the sukka.
The poskim disagree about the permissibility of decorating the sukka with verses from Scripture (Vayikra 23:42, for example), since they permitted writing down parts of the Torah only for the great need of studying it (Taz; MB 638:24). Others permit, maintaining that these decorations serve an educational purpose (Shakh; Bnei Yona). In practice, one may be lenient, as long as the verses are not written in a way that would be fit for a Torah scroll (based on Rabbeinu Yeruḥam and Tashbetz).
The beautification of the mitzva includes building a spacious sukka, well-protected from wind and sun, that is pleasant to sit in.
One must make sure not to leave dirty dishes in the sukka and not to undertake demeaning activities in it, like changing diapers and doing laundry. (See 3:2 below.)
Branches that smell foul or whose leaves fall off may not be used for sekhakh, as we are concerned that the smell or the nuisance of falling leaves will cause people to leave the sukka for home (Sukka 12b-13a). However, be-di’avad, if one did use these for sekhakh, the sukka is kosher. However, if the smell is intolerable, then the sukka is invalid on a Torah level, as it is unfit for human habitation (SA 629:14; MB ad loc. 38).
One must take precautions against fire hazards in the sukka: not leaving burning candles or unsafe electrical circuits unsupervised and keeping electric lights far away from the sekhakh. (See SA 639:1; MB ad loc. 8.)
