A.T. Robertson Commentary Mark 7:17

"And when he was entered into the house from the multitude, his disciples asked of him the parable." — Mark 7:17 (ASV)

When he was entered into the house from the multitude (οτε εισηλθεν εις οικον απο του οχλου). This detail in Mark alone, probably in Peter's house in Capernaum. To the crowd Jesus spoke the parable of corban, but the disciples want it interpreted (cf. 4:10ff.,33ff.). Matthew 15:15 represents Peter as the spokesman as was usually the case.