Matthew 21:8,9 - Coke's Commentary on the Holy Bible

And a very great multitude spread their garments— When the multitude saw Jesus mounted, they immediately bethought themselves of shewing him the honours which kings and conquerors obtained in their triumphal entries; for, as they all firmly believed that he would take the reins of government into his own hands at this passover, they had a mind to make his entry into Jerusalem have the air of a triumph. Accordingly, some spread their garments in the way, (See 2 Kings 9:13.) others cut down branches of the trees, and strewed them in the way, carrying a larger sorton high, in procession before the Messiah, as demonstrations of their joy. See Leviticus 23:40. Exodus 10:7. This seems to have reference to the feast of tabernacles, which was celebrated in joyful expectation of the Messiah's coming and tabernacling in human flesh; and these Jews testified hereby their belief in Jesus as that Messiah. Their acclamations too testified the same thing. Hosannah signifies, save, we beseech thee! and, applied to Jesus on this occasion, it was of the same import with our acclamation, God save the king! and in our language would have been expressed thus: God save the king Messiah! The next clause, Blessed is he that cometh, &c. contains nearly the words of Psalms 118:26. St. Mark says, they cried likewise, Blessed be the kingdom of our father David, which cometh, or which is to be erected now, in the name of the Lord—the Messiah. Hosannah in, or rather among the highest, means, "Let the highest orders of angels join us in praying for the prosperity of the king Messiah." We need not observe how similar the words in St. Luke, Peace in heaven, and glory in the highest, Luke 19:38 are to those of the angels on the birth of Christ, Luke 2:14. Some would render the clause, Blessed is he that cometh, &c.—Blessed in the name of the Lord is he that cometh. See the "Observations on passages of Scripture," p. 281.