Mark 4:10-13 NRSV
When he was alone, those who were around him along with the twelve asked him about the parables. And he said to them, “To you has been given the secret of the kingdom of God, but for those outside, everything comes in parables; in order that
‘they may indeed look, but not perceive,
and may indeed listen, but not understand;
so that they may not turn again and be forgiven.’ ”
And he said to them, “Do you not understand this parable? Then how will you understand all the parables?
NRSV: New Revised Standard Version