Jesus makes the distinction between those who hear his words and those who don't. He even speaks in parables so that some, even though they have ears, will not hear. But, to the disciples, he tells them to be careful how they hear. That warning applies to us also.

"And he said to them, 'Pay attention to what you hear: with the measure you use, it will be measured to you, and still more will be added to you. For to the one who has, more will be given, and from the one who has not, even what he has will be taken away.'” Mark 4:24-25