How do we know salvation is impossible with men?

Salvation is impossible by human effort for three main reasons. First, the strictness of God's law requires perfect obedience; if one offends in even one point, they are guilty of breaking the whole law (James 2:10). This highlights that no one can achieve righteousness through their works. Second, the corruption of human nature is inherent; the Bible explains that by nature, men are hostile to God and incapable of seeking Him without divine intervention (Romans 3:10-12). Finally, God's divine justice demands punishment for sin, as the soul that sins must die (Ezekiel 18:20). Only through the atoning sacrifice of Christ, who bore the wrath of God on behalf of His elect, can salvation be achieved—showing that what is impossible for man is indeed possible with God (Mark 10:27).