A.T. Robertson 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)

The most part of the multitude (ο πλειστος οχλος). See 11:20 for this same idiom, article with superlative, a true superlative (Robertson, Grammar, p. 670).

In the way (εν τη οδω). This the most of the crowd did. The disciples put their garments on the asses. Note change of tenses (constative aorist εστρωσαν, descriptive imperfects εκοπτον κα εστρωννυον showing the growing enthusiasm of the crowd). When the colt had passed over their garments, they would pick the garments up and spread them again before.