Galatians 4:22

Revised Standard Version (RSV-CI)

For it is written that Abraham had two sons, one by a slave and one by a free woman.

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And Hagar bore Abram a son; and Abram called the name of his son, whom Hagar bore, Ishmael.

So she said to Abraham, “Cast out this slave woman with her son; for the son of this slave woman shall not be heir with my son Isaac.”

But the son of the slave was born according to the flesh, the son of the free woman through promise.

But what does the scripture say? “Cast out the slave and her son; for the son of the slave shall not inherit with the son of the free woman.”

So, brethren, we are not children of the slave but of the free woman.