The farmer called all his possessions his own, forgetting that all belongs to God and humans are but stewards and tenants of all that is God's. He planned to store up and keep for the increase for himself instead of helping the poor and needy. Believers should not act like worldly people, worrying and coveting worldly wealth. The parable deals with covetousness, which is the 10th commandment. The other nine commandments are warnings of the sins that grow from coveting.
Covetousness is the most unfortunate evil of the human heart.
The lust for possessions is insatiable and is the strongest motivator in any individual's life. People believe with wealth comes power, but this is deception of how the worldly measure each other. A covetous person thinks that the good life is grounded and found in earth and material possessions. This is a distorted perspective of the human heart. The farmer's problem is that he invested his entire life in his possessions, it is not the problem that he had possessions.