The Gospel alone is our Mother

 Galatians 4:23 talks about the wives of Abraham. The one was a slave, the other was a free woman.

Then in v. 24 and 25, Paul says that these women were allegorical to the realities they represented, for they represented two covenants. Agar represented Mt. Sinai, and it's bondage of the law.

In v. 26, Jerusalem which above is free, which is the mother of us all. This is the covenant of grace. In other words, this is the gospel that has begotten us. God in Christ is our Father, who alone teaches us all things necessary for our salvation, and the gospel alone is our mother who makes us alive with Christ, and sits us with him in the heavenly realms.