Genesis 21:10
"Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac."
Cross References (ranked by relevance)
And the servant abideth not in the house for ever: but the Son abideth ever.
To an inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven for you,
And these are the generations of Isaac, Abraham’s son: Abraham begat Isaac:
Then said the king to the servants, Bind him hand and foot, and take him away, and cast him into outer darkness; there shall be weeping and gnashing of teeth.
For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise.
Wherefore thou art no more a servant, but a son; and if a son, then an heir of God through Christ.
And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him.
And Abraham said, Because I thought, Surely the fear of God is not in this place; and they will slay me for my wife’s sake.
But unto the sons of the concubines, which Abraham had, Abraham gave gifts, and sent them away from Isaac his son, while he yet lived, eastward, unto the east country.
And Abraham stretched forth his hand, and took the knife to slay his son.
But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.