A.T. Robertson Commentary Matthew 7:28

"And it came to pass, when Jesus had finished these words, the multitudes were astonished at his teaching:" — Matthew 7:28 (ASV)

The multitudes were astonished (εξεπλησσοντο ο οχλο). They listened spell-bound to the end and were left amazed. Note the imperfect tense, a buzz of astonishment. The verb means literally "were struck out of themselves."