What does the Bible say about eternal safety?

The assurance of eternal safety is explicitly addressed in 1 John 5:13, where the Apostle John writes that he has written these things so those who believe in the name of the Son of God may know they have eternal life. This certainty is grounded in faith in Jesus Christ, not in personal merit or performance. It reflects a core tenet of Reformed theology that emphasizes God's sovereign grace in salvation, where assurance is a gift of the Holy Spirit who witnesses to the truth of our salvation through the Word.