How shall we liken? (Πως ομοιωσωμεν?) Deliberative first aorist subjunctive. This question alone in Mark. So with the other question:

In what parable shall we set it forth? (εν τιν αυτην παραβολη θωμεν;). Deliberative second aorist subjunctive. The graphic question draws the interest of the hearers (we) by fine tact. Luke 13:18 retains the double question which Matthew 13:31 does not have, though he has it in a very different context, probably an illustration of Christ's favourite sayings often repeated to different audiences as is true of all teachers and preachers.