How do we know that God has elected some for salvation?

The doctrine of election is firmly rooted in Scripture, particularly in Romans 9, where Paul discusses God's sovereign choice between Jacob and Esau before they were born. Verses 10-14 illustrate that God's electing grace is not based on human works or merits but solely upon His sovereign will. This election is a tangible display of God's mercy, as He states in Romans 9:15, 'I will have mercy on whom I will have mercy.' Thus, the assurance of salvation stems from God's unchanging decree of election, reflecting His love and purpose from eternity.