When we hear something over and over, we tune it out at some level. It becomes too familiar, or we tune it out because we don't want to hear it.

This is what children do with their parents. "Are you listening to what I'm telling you?" Um, that would be no! When we hear an ad or announcement repeated ad nauseam, we tune it out as a means of self-preservation.

Perhaps this is why people are indifferent to the good news of God's redemption. They either tune it out because it's redundant and repetitive, or they just don't want to hear it. Then again, it could be something quite different.