John Nelson Darby discusses the interpretation of the parables of the Treasure and the Net in Matthew 13, emphasizing the importance of understanding the kingdom of heaven as a singular concept viewed from different perspectives. He critiques interpretations that conflate the parables with new dispensations or mix the roles of Christ and the angels in judgment. Darby highlights the distinction between the outward effects of the gospel and God's intentions, noting that the parables illustrate both man's responsibility and divine purpose. He asserts that the gathering of good and bad fish in the net represents the work of fishermen, while the final judgment is the role of angels, underscoring the need for clarity in understanding these spiritual truths.