Now, you, my brothers and sisters, are God’s children as a result of his promise, just as Isaac was.” (Galatians 4:28, GNB)

We are “children of promise” (ESV) as a result of God’s work and God’s promise, not as a result of our own effort to please him.  Paul has already told his readers that we are redeemed and adopted by God

But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons.” (Galatians 4:4–5, ESV)

As a result of this redemption and adoption we are now children of the promise, a fact that Keith and Kristyn Getty and Stuart Townsend capture very well in their hymn By Faith:

By faith we see the hand of God
In the light of creation’s grand design
In the lives of those who prove His faithfulness
Who walk by faith and not by sight

By faith our fathers roamed the earth
With the power of His promise in their hearts
Of a holy city built by God’s own hand
A place where peace and justice reign

We will stand as children of the promise
We will fix our eyes on Him our soul’s reward
Till the race is finished and the work is done
We’ll walk by faith and not by sight

By faith the prophets saw a day
When the longed-for Messiah would appear
With the power to break the chains of sin and death
And rise triumphant from the grave

By faith the church was called to go
In the power of the Spirit to the lost
To deliver captives and to preach good news
In every corner of the earth

We will stand…

By faith this mountain shall be moved
And the power of the gospel shall prevail
For we know in Christ all things are possible
For all who call upon His name

We will stand as children of the promise

Indeed we will.