Now the promises were spoken to Abraham and to his descendant. ¹  Scripture ²  does not say, “and to the descendants,” ³  referring to many, but “and to your descendant,” ⁴  referring to one, who is Christ.

But what does the scripture say? “Throw out the slave woman and her son, for the son of the slave woman will not share the inheritance with the son” ¹  of the free woman.