Charles H. Spurgeon on Psalms 118:25

Save now, I beseech thee, O Lord, etc. Hosanna. The cry of the multitudes as they thronged in our Lord's triumphal procession into Jerusalem (Mt 21:9,18 Mr 11:9,15 Joh 12:13) was taken from this Psalm, from which they were accustomed to recite Ps 118:25-26 at the Feast of Tabernacles. On that occasion the great Hallel, consisting of Psalms 113-118 was chanted by one of the priests, and at certain intervals the multitudes joined in the responses, waving their branches of willow and palm, and shouting as they waved them, Hallelujah, or Hosannah, or, "O LORD, I beseech thee, send now prosperity." This was done at the recitation of Ps 118:1,29; but according to the school of Hillel, at the words "Save now, we beseech thee." The school of Shammai, on the contrary, say it was at the words, "Send now prosperity." Rabban Gamaliel and R. Joshua were observed by R. Akiba to wave their branches only at the words, "Save now, we beseech thee" (Mishna, Succah, 3. 9). On each of the seven days during which the feast lasted the people thronged the court of the temple, and went in procession about the altar, setting their boughs bending towards it; the trumpets sounding as they shouted Hosannah. But on the seventh day they marched seven times round the altar, shouting meanwhile the great Hosannah to the sound of the trumpets of the Levites (Lightfoot, Temple Service, 16. 2). The very children who could wave the palm branches were expected to take part in the solemnity (Mishna, Succah, 3. 15; Mt 21:15). From the custom of waving the boughs of myrtle and willow during the service the name Hosannah was ultimately transferred to the boughs themselves, so that according to Elias Levita (Thisbi. sv), "the bundles of the willows of the brook which they carry at the Feast of Tabernacles are called Hosannahs." William Aldis Wright, in "Smith's Dictionary of the Bible," 1863.