How do we know that eternal life is a promise for believers?

Eternal life is guaranteed to believers based on the finished work of Christ, who is the good shepherd that lays down His life for His sheep. Romans 8:10 states that if Christ is in you, even though the body is dead because of sin, the Spirit is life because of righteousness. This underscores that believers have a guaranteed hope of eternal life, fully realized in the resurrection. The assurance of salvation and eternal life is rooted not in our actions but in Christ’s righteousness imputed to us, fulfilling the promise made in Scripture that believers will dwell in the house of the Lord forever.