How do we know all Israel shall be saved?

Romans 11:26 states, 'And so all Israel shall be saved,' which affirms God's promise of salvation for His chosen people. This verse is often discussed within the context of God's covenant relationship with Israel, illustrating that salvation is not merely about ethnic lineage, but spiritual inclusion in God’s redemptive plan. The 'all' referred to here signifies those who are 'in Christ', chosen before the foundation of the world and inscribed in the Lamb's Book of Life. Thus, while there may be a distinction between physical Israel and spiritual Israel, the promise shows that God will not lose any of His elect. This assurance stems from God's immutable and sovereign will, ensuring that every chosen individual will come to salvation.