Features Added Later. A custom that came to be practiced later, possibly alluded to in the Christian Greek Scriptures (Joh 7:37, 38) but not in the Hebrew Scriptures, was the drawing of water from the Pool of Siloam and pouring it, along with wine, on the altar at the time of the morning sacrifice. According to most scholars, this occurred on seven days of the festival but not on the eighth. The priest would go to the Pool of Siloam with a golden pitcher (except on the opening day of the festival, a sabbath, when the water was taken from a golden vessel in the temple, to which it had been carried from Siloam on the preceding day). He would time himself so as to return from Siloam with the water just as the priests in the temple were ready to lay the pieces of the sacrifice on the altar. As he entered the Court of the Priests by the temple Water Gate he was announced by a threefold blast from the priests’ trumpets. The water was then poured out into a basin leading to the base of the altar, at the same time that wine was being poured into a basin. Then the temple music accompanied the singing of the Hallel (Psalms 113-118), during which time the worshipers waved their palm branches toward the altar. This ceremony may have reminded the joyful celebrators of Isaiah’s prophetic words: “With exultation you people will be certain to draw water out of the springs of salvation.”​—Isa 12:3.

The waving of palm branches by the people at this festival reminds us also of the crowds that waved palm branches during Jesus’ entry into Jerusalem just before his death, although this did not occur at the time of the Festival of Booths, but, rather, prior to the Passover. (Joh 12:12, 13) Again, the apostle John, who saw in vision 144,000 of God’s slaves sealed in their foreheads, tells us: “After these things I saw, and look! a great crowd, which no man was able to number, out of all nations and tribes and peoples and tongues, standing before the throne and before the Lamb, dressed in white robes; and there were palm branches in their hands. And they keep on crying with a loud voice, saying: ‘Salvation we owe to our God, who is seated on the throne, and to the Lamb.’”​—Re 7:1-10.