* Who is the husband of Sarah?
* Who was the husband of Sarah?
* If she and her husband lived a long long time ago, surely their dead by now.
As in: "The late (deceased) Douglas Adams is a treasured English writer"?
[CAUTION: I am not a teacher:take the advice and or corrections offered in this post at your own risk.
If you doubt the information, please get a qualified opinion from one of the teachers on these forums.]
Apply the same ingenious logic that you did to the first example, it depends on the perspective from which you are discussing Abraham.
Abraham is the father of Issac. (in the Bible/in history, which will not/cannot change)
Abraham was the father of Issac. (before he passed on)
Okay, now I get it. Thanks!