The last parable in this series is at least partially interpreted by Jesus. A large net was used to indiscriminately gather fish, which were subsequently sorted. This parable is somewhat parallel to the weeds story earlier in the chapter.
Bad fish are thrown away and good fish are kept. Does this apply to the world, to the church, or both?
There is a day of judgment coming when evil people will be separated from the righteous ones. There is every reason to believe that this judgment will include the church. Even in Matthew’s day, there were already rotten fish in the church.
Jesus finishes off this series by asking the disciples if they understand, and they do understand. He then compares discipleship to scribal studies, a rigorous course of understanding the Bible. Jesus says the scribe-disciple will display the kingdom treasures. There are new treasures brought by Jesus, but the old treasures of scripture are not to be ignored.
I don’t hear much preaching from the OT. I’ve been trying to improve my OT game in recent years to make up for that lack. It is a treasure.
I’m always surprised when people in the church show no desire to learn more about the Bible, about Jesus, about God. Of course, some do, but most do not. Based on this passage, I’d say Jesus expects his disciples to be fairly rigorous in their pursuit of understanding scripture. Am I wrong?