He’s describing someone who hears the gospel and doesn’t truly perceive and understand the implications of what’s being taught. Not because they can’t understand, but because they don’t want to see the truth. They can hear the words, but refuse to let the word in. We often think hard hearts are the result of people that have been hurt or wounded. So much so they’ve been jaded or cynical, and disillusioned. But most often hard hearts come from a prideful rebellion of God.