How do we know that salvation is possible only through God?

The assurance that salvation is possible only through God comes from various scriptures that highlight God’s sovereignty and mercy. For example, in Ephesians 1:4-5, it states that God chosen us in Christ before the foundation of the world, which emphasizes that salvation is not based on our actions but on God’s eternal purpose. Romans 8:30 further demonstrates that those whom God predestines, He also calls and justifies. Therefore, all aspects of salvation—from election to glorification—are orchestrated by God's sovereign will and power, confirming that we can do nothing to achieve salvation on our own.