How do we know Christ is all we need?

According to Luke 12:21, those who lay up treasure for themselves and are not rich toward God are labeled as fools. The sermon emphasizes that Christ is everything, and anything that comes between us and Him becomes an idol. Our works and efforts in this life cannot satisfy our souls or secure our standing before God. The richness before God is solely found in Christ's righteousness and sacrifice, indicating that true wealth is not earthly possessions but a relationship with Christ. Only in Him do we find everything necessary for our spiritual well-being.