1,198. Taking the Lulav in the Temple and Elsewhere
Hilchos Shofar, Succah v’Lulav 7:12
If one binds the lulav, the myrtle and the willow but he separates the lulav from the myrtle with a cloth or something similar, it is considered an interposition. If he separates them with myrtle leaves, it is not considered to be a interposition because something does not form an interposition with its own type. One may bind the species using a string, a cord, or anything else that he likes because binding the species is not a necessary component of the mitzvah.
Hilchos Shofar, Succah v’Lulav 7:13
The mitzvah to take the lulav in every place and at every time, even on Shabbos, refers to the first day of Succos, as per Leviticus 23:40, “On the first day, you shall take....” It was only in the Temple that it was taken on all seven days of the holiday, as the verse continues, "and you shall rejoice before Hashem your God for seven days.” When Shabbos falls during the last six days, the lulav is not taken on Shabbos out of concern that a person might come to carry it four cubits (about six feet) in the public domain, the same as was enacted regarding the shofar on Rosh Hashana. [Please note: our practice is not to take the lulav even on the first day if it falls on Shabbos. See later, halachos 7:17-18.]