How do we know that not everyone is saved?

The existence of hell and those who occupy it suggests that God has not chosen to save every individual. If God, being Almighty, truly aimed for the salvation of every person, then none would find themselves in a state of condemnation. The Apostle Paul presents this dilemma as a clear challenge to the notion that God's desire automatically entails action without divine purpose. Romans 9:22-24 illustrates God's sovereignty in having mercy on whom He wills, showing that His choice in salvation is not arbitrary but is based on His purpose. Salvation, thus, is intentional and limited to those God has chosen to save.