What does Luke 8:6 mean?

This continues Jesus' parable of the sower. In His first example, seeds fall on the hard path where people crush them with their feet and birds take them away. In this second example, the seeds land on rocky soil. Modern readers tend to picture this soil as good dirt with a lot of rocks sticking out of the surface. That's not what is described, here. Jesus is implying a base of stone with a thin layer of dirt on top. Unless the dirt has been prepared in advance, the person casting seeds won't realize it's so shallow.

Both Matthew and Mark say the soil allows the seed to grow quickly. Yet the rock underneath causes shallow roots; when the sun gets hot, the plants wither and die (Matthew 13:5–6; Mark 4:5–6). Luke, perhaps because he is a doctor, gives the specific reason the plants die: they have no moisture. Because of the bedrock, the soil can't hold the moisture the plants need. Jesus compares this soil to people who hear God's word with a shallow kind of understanding and acceptance. They don't allow the message to reach into their hearts, so when they are tested, they abandon what little understanding they have (Luke 8:13).

How does this apply to listening well? We can choose whether to be shallow people or not. We can choose to have a depth of character that can take in God's Word, consider it, and act on it. We don't have to happily take in the initial good news Jesus offers but refuse to follow up with discipleship and sanctification. Acknowledging only the parts of God's Word that sound pleasant and easy will not lead to a firm faith that can withstand life's inevitable trials.