{Explain unto us} (diasaph(8873)on h(886d)in). Also in  18:31 .
"Make thoroughly clear right now" (aorist tense of urgency). The
disciples waited till Jesus left the crowds and got into the
house to ask help on this parable. Jesus had opened up the
Parable of the Sower and now they pick out this one, passing by
the mustard seed and the leaven.