From The Gospel of Matthew, by Curtis Mitch and Edward Sri, commenting on Matthew 13:44-52
At the end of the discourse Jesus asks his disciples if they understand all these things, referring to the parables taught that day.
Their affirmative response is significant. Understanding of the parables is precisely what Jesus said the crowds would lack (13:13–15). But truly hearing the word and understanding it is the chief characteristic of the seed that falls on good soil and bears fruit (13:23). Though the disciples still have much to learn, they do at least have an understanding of the kingdom’s mysteries that sets them apart from the crowds (13:10–17) and will make them fruitful in their mission (13:23).
Jesus says the disciples are like a scribe, a scholar of Scripture who was trained in interpreting the law. According to the book of Sirach, a true scribe can “penetrate the subtleties of parables” and be “at home with the obscurities of parables” (Sir 39:2–3 RSV). Unlike the scribes associated with the Pharisees who oppose Christ (12:38), Jesus’ disciples understand the parables. They are the new scribes of the kingdom because they have been instructed (literally, “discipled”) in the kingdom of heaven.
Jesus also says the disciples are like the head of a household who brings from his storeroom both the new and the old. As men who understand the mysteries of the kingdom, they see how Christ’s ministry (“the new”) fulfills the Hebrew Scriptures (“the old”), bringing God’s plan of salvation to its climax. Therefore the disciples are much better interpreters of the Scriptures—and thus better scribes—than the scribes allied with the Pharisees who have rejected Jesus (see 12:38).