What does Mark 4:34 mean?
The Greek verb tense of this verse suggests the disciples regularly asked Jesus for clarification after He taught crowds with parables. This means they are the good soil (Mark 4:8) who choose to hear and understand Jesus' message (Mark 4:9, 23), and who have been chosen to continue Jesus' work (Mark 3:13–15).A parable is somewhat like a movie trailer, or an advertisement. It reveals a little about the purpose, use, or characters of what's being presented, but it isn't the movie or product itself. Parables are designed to woo people and invite them into a deeper relationship with the teacher and the subject matter. Parables don't hit listeners over the head with theology, but reveal which of the listeners want to know more. It is these—the seekers who want greater understanding—who will be left by Christ to explain the gospel after His resurrection and ascension. Then the teaching will become clearer. The parables are a vetting process for future teachers.
In Matthew's account, Jesus quotes Psalm 78:2. He says, "This was to fulfill what was spoken by the prophet: 'I will open my mouth in parables; I will utter what has been hidden since the foundation of the world'" (Matthew 13:35). Parables take God's hidden truth and summarize it with an easier-to-describe situation; this draws the interest of whoever wants to know that truth. Those who follow a search for truth, and dig into the deeper meaning, are those Jesus calls His disciples and His family (Mark 3:31–35).