Some of the multitude (εκ του οχλου). Τινες (some) to be supplied, a common Greek idiom.

Of a truth (αληθως). "Truly." See John 1:47.

The prophet (ο προφητης). The one promised to Moses (Deuteronomy 18:15) and long expected. See on John John 1:21. Proof of the deep impression made by Jesus.