Knowing in himself (ειδως εν εαυτω). Second perfect active participle of οιδα. See John 2:25 for this supernatural insight into men's minds.

Murmured (γογγυζουσιν). Present active indicative retained in indirect discourse. See John 6:41 for γογγυζω.

At this (περ τουτου). "Concerning this word."

Cause to stumble (σκανδαλιζε). Common Synoptic verb from σκανδαλον for which see Matthew 5:29. In John again only in John 16:1.