Using One’s Own Lulav

If the first day of the festival falls on the Sabbath, all the people bring their lulavim to the synagogue [on Friday, as it is prohibited to carry it there on the Sabbath]. The next day they arise early [and come to the synagogue], and each one recognizes his own [lulav] and takes it, since the sages said one cannot fulfill his obligation on the first day of the festival with his friend’s lulav. But on the other days of the festival one may fulfill his obligation with the lulav of his fellow.