How do we know that God's choice of heirs is true?

The assurance of God's choice of heirs comes from the historical narrative presented in Scripture, particularly in the promises given to Abraham. In Genesis 15, God explicitly denotes Isaac, the child of promise, as the true heir, a theme echoed by Paul in Galatians 4, illustrating the distinction between children of the flesh and children of promise. Ephesians 1 affirms that this choice was made before the foundations of the world, indicating that it is an eternal decree rather than a temporal decision, further substantiating the reality of God's predetermined inheritance for His people.