Shared ground
Jesus answers a practical question: why he teaches the crowds with parables (v.10). He explains that understanding the “mysteries” (previously hidden realities now being made known) of God’s reign is granted to the disciples, while it is “not given” to others in the crowd (v.11). That difference shows up in what people do with what they hear.
Jesus then gives a principle about growth and loss: those who “have” receive more, and those who do not “have” lose even what they “have” (v.12). In the flow of the passage, “having” is tied to real hearing and understanding, not just exposure to teaching (vv.13–15).
Jesus says parables relate to this mixed response: many people see and hear but do not truly grasp (v.13). Isaiah’s words describe the condition behind the failure—calloused hearts, dulled ears, and eyes that have been closed (vv.14–15). By contrast, the disciples are called “blessed” because they do see and hear, and because they live in a moment many earlier faithful people longed to witness (vv.16–17; see Matthew 13:10–17).
Where interpretation differs
One question is who “them” refers to in v.11. Some read it broadly as the crowd as a whole; others narrow it to the unresponsive portion of the audience (those already resisting).
Another question is how to relate “it is given” (v.11) to human response (vv.13–15). Some emphasize God’s giving as the main reason some understand; others emphasize that the giving is connected to prior receptivity, so that people’s refusal is a key part of why they remain in the dark.
A third question is what parables mainly do. Some read Jesus as saying parables are designed primarily to conceal from hardened hearers; others say parables both reveal and conceal at the same time—revealing truth to receptive listeners while exposing the lack of understanding in resistant listeners.
A final question is what “fulfilled” means regarding Isaiah (v.14). Some take it as a direct prophetic prediction coming true in Jesus’ day; others take it as a repeated pattern—Isaiah’s description fits what is happening again.
Why the disagreement exists
The passage holds two lines of explanation together: (1) understanding is “given” (v.11), and (2) the people’s own perceptual and moral condition is described as the reason they do not understand (vv.13–15). Interpreters differ on which line is foregrounded and how tightly they are linked.
What this passage clearly contributes
Explicitly, the text presents understanding of God’s reign as a gift and portrays receptivity as something that can deepen or diminish (vv.11–12). It also portrays parables as functioning in a divided audience: the same teaching results in insight for some and confirmed non-understanding for others (vv.13–15). Finally, it frames the disciples’ understanding as a privileged moment in salvation history: what they are seeing and hearing is what earlier “prophets and righteous” longed for (vv.16–17).