• the fruit of a beautiful tree (Etrog)
• the branches of date palms (Lulav)
• the branches of the myrtle tree (Hadasim)
• the branches of the willow tree (Aravot)

The Four Species are plainly called Lulav and Etrog. The etrog or citron is a yellow citrus fruit about the same size as a lemon. But it is much sweeter in order to be known as the fruit of beautiful trees. The branches of a palm, a myrtle, and a willow are bound together. The three branches are held in the right hand, and the etrog is held on the left. They are then waved together in the Hebraic directions of east, south, west, north, up and down. By waving these Four Species together, the people of God are proclaiming that God rules over all nature and all nations throughout all generations. Since the palm branch or the lulav is the stiffest and the most prominent element of the Four Species, the whole ceremony is called the waving of the lulav.

The expression "And you shall take for yourselves on the first day" implies that one's ownership is required on the first day. On the other six days, ownership is not strictly required.

All the Four Species are required to fulfil this commandment. If any one of the species is missing, the law is not being fulfilled. One Lulav, one Etrog, two Aravot and three Hadasim are bound and presented in a manner that they are beautiful to behold. This is done in love for God and not for the purpose of showing off to the neighbors.

Three explanations for the Four Species are as follows:

With Respect To The Total Man

The shape of the citron (Etrog) resembles the human heart, the driving force behind all our actions. The palm branch (Lulav) resembles the spine, which holds the body together and, without which, we would be unable to move. The almond-shaped myrtle branches (Hadasim) resemble the eyes, with which we behold God's world. And the willow branches (Aravot) resemble the lips, with which we express our thoughts and feelings. By holding these four together, we show that we should love God with all of our heart, soul, mind and strength.

With Respect To The Torah

The fruit of the citron (Etrog) has both a pleasant taste and a pleasant aroma, symbolizing one who possesses both the blessings of knowledge of Torah and of good deeds. The fruit of the date palm (Lulav) has good taste but no aroma, symbolizing the person who has Torah knowledge but no good deeds. The myrtle (Hadasim) is fruitless and it has a pleasant aroma, symbolizing the person who has good deeds but no Torah. And the willow branch (Aravah) has neither pleasant taste nor aroma, symbolizes the person who has neither Torah nor good deeds. Holding these four in a tight bond represents the unity that God desires for His People. The bond represents the conversion of a set of separate individuals into a People. He who gathered much had nothing over, and he who gathered little had no lack (Exodus 16:18). The blessing of this whole group is far greater than each of the individual blessings combined together. Everyone is blessed!

With Respect To Jews And Gentiles

The palm, myrtle, and willow branches represents the Jews believers, and the etrog represents the Gentile believers. In Deuteronomy 16:14, the stranger is the Gentile who has joined himself to Israel. At the start of the ceremony, the etrog is upside down. This is symbolic of us being upside down before we came to God. It is then turned right side up and joined to the other three. This represents the coming together of the One New Man (Ephesians 2:11-16) in holy matrimony with Christ. After we are turned right side up in returning to God, we are joined to Him in marriage – both Jews and Gentiles in one union with the Messiah.

A better and simpler explanation for the 4 species is as follows:

But God desires even the willows to be saved - those without Torah and any good deeds! Desiring that none should perish, God commands us to play our roles in blessing the willows with our fragrance and fruit. Like the body, all parts are required.

1 Corinthians 12:22-25
No, much rather, those members of the body which seem to be weaker are necessary.
And those members of the body which we think to be less honorable,
on these we bestow greater honor; and our unpresentable parts have greater modesty,
but our presentable parts have no need.
But God composed the body, having given greater honor to that part which lacks it,
that there should be no schism in the body,
but that the members should have the same care for one another.

One without the other is incomplete. The 4 species must be waved together before God!