Albert Barnes Commentary Leviticus 23:40

"And ye shall take you on the first day the fruit of goodly trees, branches of palm-trees, and boughs of thick trees, and willows of the brook; and ye shall rejoice before Jehovah your God seven days." — Leviticus 23:40 (ASV)

The boughs of goodly trees - Or, the fruit (see the margin) of the citron trees. It is said that every Israelite at the Feast of Tabernacles carried in one hand a bundle of branches and in the other a citron. The branches seem to have comprised the boughs of palm-trees, thick trees and willows here named. See the note to Leviticus 23:42; Nehemiah 8:15–16.