A.T. Robertson Commentary Mark 11:5

"And certain of them that stood there said unto them, What do ye, loosing the colt?" — Mark 11:5 (ASV)

Certain of those that stood there (τινες των εκε εστηκοτων). Perfect active participle, genitive plural. Bystanders. Luke 19:33 terms them "the owners thereof" (ο κυριο αυτου). The lords or masters of the colt. They make a natural protest.