Some of the multitude (ek tou ochlou). Tines (some) to be supplied, a common Greek idiom.
Of a truth (alēthōs). “Truly.” See Joh 1:47.
The prophet (ho prophētēs). The one promised to Moses (Deu 18:15) and long expected. See note on Joh 1:21. Proof of the deep impression made by Jesus.