John Gill 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)

And when he was entered into the house
Very probably at Capernaum, and it may be the house of Simon and Andrew, where he used to be when there:

from the people ;
being separated from them, having dismissed and left them, when he and his disciples were by themselves alone:

his disciples asked him concerning the parable ;
that saying of his to the people, which was somewhat dark and intricate to them; that nothing without a man going into him defiled him, but what comes out of him: this was asked by Peter, in the name of the rest; (See Gill on Matthew 15:15).