Leviticus 23:40 - Matthew Poole's English Annotations on the Holy Bible

Boughs, Heb. the fruit, i.e. fruit-bearing boughs, or branches with the fruit on them, as the word fruit seems to be taken, 2 Kings 19:30 Ezekiel 19:12. Goodly trees, to wit, the olive, myrtle, and pine, as they are mentioned, Nehemiah 8:15,16, which were most plentiful there, and which would best preserve their greenness or freshness. Thick trees, fit for shade and shelter. Willows of the brook, which might do well to mix with the other, and in some sort to bind them together. And as they made their booths of these materials, as is apparent from Ne 8, so it seems they did also carry some of these boughs in their hands, as is affirmed by Jewish and other ancient writers. Ye shall rejoice; which joy they testified by feasting, thanksgiving, &c.