What does the Bible say about being children of the promise?

In Galatians 4, Paul vividly illustrates the distinction between those born of the flesh and those born of the promise through an allegory of two mothers: Hagar and Sarah. Paul concludes that Christians, like Isaac, are children of the promise. This means that they are heirs to God's covenant blessings not based on their own merit or lineage, but through the sovereign grace of God and the faith bestowed upon them. Romans 8:17 supports this understanding by stating, 'Now if we are children, then we are heirs—heirs of God and co-heirs with Christ.' Thus, believers find their identity as children of promise in their relationship with Christ.