How do we know true believers will not become apostate?

The assurance of a true believer's salvation lies in God's promise that those He has saved will be preserved until the end. Ephesians 4:8-11 serves as a reminder that God has given gifts to the church, including preachers who edify and mature the saints. True believers exhibit a desire for the Word of God, cultivate their faith despite life's challenges, and their hearts are drawn toward worship. Ultimately, their confidence is not in themselves but in God's faithfulness, knowing they are held securely in His hands, as Jesus states in John 10:28-29.