5 Bible Verses about Concubines

For it is written that Abraham had two sons, one by the slave woman and one by the free woman; but while the son by the slave woman was born according to the flesh, the son by the free woman was born in fulfilment of a promise.

but just as in old times the son born by the flesh used to persecute the son born by the power of the Spirit, so also it is now.

they are not all children of Abraham because they are Abraham's descendants. The promise was, In Isaac shall thy posterity be called.

But what does the Scripture say? Send away the slave-woman and her son; for the slave's son shall not be heir along with the son of the free woman.

of whom it had been said, It is through Isaac that your posterity will be traced.