A.T. Robertson Commentary John 6:41

"The Jews therefore murmured concerning him, because he said, I am the bread which came down out of heaven." — John 6:41 (ASV)

Murmured (εγογγυζον). Imperfect active of the onomatopoetic verb γογγυζω, late verb in LXX (murmuring against Moses), papyri (vernacular), like the cooing of doves or the buzzing of bees. These Galilean Jews are puzzled over what Jesus had said (verses 33,35) about his being the bread of God come down from heaven.