Genesis 24:36

Modern King James Version

And Sarah my master's wife bore a son to my master when she was old. And he has given to him all that he has.

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And she said to Abraham, Cast out this slave woman and her son. For the son of this slave woman shall not be heir with my son, with Isaac.

And Abraham gave all that he had to Isaac.

And not being weak in faith, he did not consider his own body already dead (being about a hundred years old) or the deadening of Sarah's womb.