'Heir' in the Bible

You and your sons and your servants shall cultivate the land for him, and you shall bring in the produce, so that your master’s grandson may have food to eat; but Mephibosheth, your master’s grandson, shall always eat at my table.” Now Ziba had fifteen sons and twenty servants.

And, behold, the whole family is risen against thine handmaid, and they said, Deliver him that smote his brother, that we may kill him, for the life of his brother whom he slew; and we will destroy the heir also: and so they shall quench my coal which is left, and shall not leave to my husband neither name nor remainder upon the earth.