Son of Abraham and Sarah, father of Jacob and Esau (5)
I believe the answer is:
isaac
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">son of abraham and sarah</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">father of jacob and esau</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for isaac that I've seen before include "Sacrificial offering" , "Newton's first name" , "one almost sacrificed" , "According to the book, twins' dad" , "Sir -- Newton, English scientist" .)