What does Mark 4:18 mean?

As the sower sows his seeds (Matthew 4:1–9), some land in a patch filled with thorns. The word translated "thorn" is from the Greek root word akantha and is the same word used when describing the crown of thorns Jesus wore on the cross (Matthew 27:29).

In the parable, the soil is good enough to nurture thorny plants, so the seed germinates and grows. But the weeds choke the plant before it can develop grain. The spiritual equivalent would be someone who hears the gospel, allows the message to reach his heart, and even shows some spiritual growth, but doesn't display any spiritual fruit (Galatians 5:22–23).

These are the people who see Jesus as a good teacher and Christianity as a unique kind of self-help. They may take biblical principles and apply them to their family or marriage or business. They are drawn to the morality of Christianity, and have the appearance of spiritual growth. What these persons don't understand is that "spiritual growth" is only authentic if it is empowered and directed by the Holy Spirit. The "fruit of the Spirit" isn't a list of attitudes to strive for, but the natural result of allowing the Holy Spirit to work in us (Philippians 2:13).

It is these people who believe they can work for their salvation while keeping one foot in the world. They don't understand that they are interpreting the gospel through the world's point of view, and that same world will not let go easily (Mark 4:19; Matthew 6:24).