Leviticus 23:39-44

A further instruction respecting the Feast of Tabernacles is appended. When ye have gathered in the fruit of the land, not necessarily at the completion of the ingathering, but at the time at which the festival is held, ye shall take you on the first day the boughs of goodly trees. The word in the Hebrew, in its literal acceptation, means fruits of goodly trees, and hence in later times a misunderstanding arose (see 2 Macc. 10:6, 7), which led to the graceful practice of carrying in the left hand citrons (the fruit of goodly trees), and in the right hand myrtles, palms, and willows. It appears, however, that the word signifies in this place rather products than fruits, namely, leaves and branches. The command, therefore, would be, ye shall take you … products of goodly trees, branches of palm trees, and the boughs of thick trees, and willows of the brooks. Originally, the purpose of these boughs was to make booths, as is shown by Nehemiah 8:15, Nehemiah 8:16, "Go forth unto the mount, and fetch olive branches, and pine branches, and myrtle branches, and palm branches, and branches of thick trees, to make booths, as it is written. So the people went forth, and brought them, and made themselves booths." And ye shall rejoice before the Lord your God seven days. Accordingly we find when the feast was observed by Ezra, after the long interval from the days of Joshua, "there was very great gladness" (Nehemiah 8:17). The reason of the injunction to dwell in booths is that your generations may know that I made the children of Israel to dwell in booths, when I brought them out of the land of Egypt; that is, on the first night after they had been delivered from Egypt, and encamped at Succoth (Exodus 12:37).