How do we know that sin is the root problem of unbelief?

In the sermon, it is emphasized that all external problems — whether financial, relational, or health-related — are symptoms of a deeper issue: sin and unbelief. The Bible indicates that every sin stems from a lack of faith in God’s promises and character. For example, the apostle Paul, facing his own 'thorn in the flesh,' learned that God's grace was sufficient, steering his focus from the external challenge to the internal battle of trust (2 Corinthians 12:9). Thus, our inability to trust God accurately reveals how deeply rooted sin is in our lives.