Albert Barnes Commentary Mark 4:13

"And he saith unto them, Know ye not this parable? and how shall ye know all the parables?" — Mark 4:13 (ASV)

Know ye not this parable? This parable, which is so plain and obvious.

How then will ye know all parables? Those which are more difficult and obscure. Since they themselves were to be teachers, it was important that they should understand the whole system of religion—a matter of much more importance for them at that time than for most people.