Q. In response to a previous question, you said, “Parables were the perfect vehicle for Jesus’ purposes because they either reveal or conceal the message, depending on the state of a person’s heart. They reveal the truth to those who are open to it, but conceal it from those who aren’t ready for it yet.”
The disciples’ hearts were obviously open to Jesus’ teachings, and Jesus definitely knew that, and he explained the parables to them in private. However, there could also have been people in the crowd who had open hearts, i.e. their state of mind was open, and they were willing to listen. Nevertheless, because they were not Jesus’ disciples, they didn’t have the chance to hear Jesus’ elaboration.
I have been thinking about this for a while now … is it because Jesus “had plans” for those non-disciples to understand the same truth some other time via some other means? Would appreciate if you could help me understand. Thanks.
Let me say two things in response to your question.
First, when we see the expression “the disciples,” we shouldn’t necessarily understand that to mean only the twelve disciples whom Jesus chose to be apostles. That is the meaning in some places in the gospels, but in other places the word “disciples” refers to anyone who was following Jesus closely in order to understand his message and live by it. For example, when Luke introduces what is known as the Sermon on the Plain, he says, “A large crowd of his disciples was there and a great number of people from all over Judea, from Jerusalem, and from the coastal region around Tyre and Sidon, who had come to hear him and to be healed of their diseases.” So Luke distinguishes between “his disciples” and the others who came to hear on this occasion, and the disciples were a “large crowd.”
The word “disciples” also means more than just the twelve apostles in the episode you are asking about, in which Jesus tells the Parable of the Sower. Matthew says that after Jesus told this parable, “The disciples came to him and asked, ‘Why do you speak to the people in parables?'” Luke says similarly, “His disciples asked him what this parable meant.” But Mark elaborates a bit more about who these “disciples” were: “When he was alone, the Twelve and the others around him asked him about the parables.” So I think we should understand that in this case, as likely in other cases, anyone with an open heart could remain after the teaching and listen in on the explanation.
The second thing I would say in response to your question is that the people who heard these explanations and elaborations from Jesus did not treat them as something they were supposed to keep to themselves. They shared them with others. That is how the explanations got to be included in the gospels: They became part of the oral tradition that was handed down to later generations from those who saw and heard Jesus, which provided the content of the gospels. And I would say that the “disciples” (probably a large number) who heard these explanations got the impression from Jesus himself that they were supposed to share them with anyone who had an open heart and mind.
So even in Jesus’ own time, the explanations would have fanned out by word of mouth into the crowds for open-hearted people to hear, and down through the years they would have circulated ever more widely. Now that they are part of the Bible, they have gone around the world. So Jesus himself set in motion the process that has made these explanations available to anyone, anywhere who truly wants to understand and obey.
Good Question 
Thank you for this explanation. I’m a mature believer and never understood this before. Now it makes so much more sense. Disciples = likely more than the original twelve. Explanations of parables = intended to spread by word of mouth over time. We read them here ourselves today.