Galatians 4:21-31
In showing that the heart of the gospel is trusting in God’s work for us in Jesus Christ, rather than relying on our own capabilities, Paul uses the Old Testament story of Sarah and Hagar to illustrate the call to rely on God’s power and grace. The good news of Jesus Christ is especially for the barren, for those who see themselves as failures, because they are those whom God reaches out to first.