Charles Ellicott Commentary Matthew 21:8

"And the most part of the multitude spread their garments in the way; and others cut branches from the trees, and spread them in the way." — Matthew 21:8 (ASV)

And a very great multitude — Better, the greater part of the multitude. Part of the crowd had come with Him from Galilee, and part streamed from Bethany, excited by the recent resurrection of Lazarus (John 12:17). Some went before Him, and some followed. As they advanced, they were met by a fresh crowd pouring forth from Jerusalem. Of the latter, St. John records that they came out with palm branches in their hands, as if to salute a king with the symbols of his triumph .

Spread their garments in the way — This, again, was a recognized act of homage to a king. So Jehu, when the officers of the army of Israel chose him as their ruler, walked upon the garments they spread beneath his feet (2 Kings 9:13). So Agamemnon, tempted to an act of barbaric pomp after the manner of Eastern kings, entered his palace at Mycenae walking on costly carpets (Aeschylus, Agamemnon 891).