אור החיים — ויהיו חיי שרה... שני חיי שרה

Q — Why does the verse open with the seemingly redundant 'ויהיו חיי שרה' and close again with 'שני חיי שרה'?

A — Or HaChaim reads 'ויהיו' (a term Chazal associate with distress) as alluding to the midrash that Sarah died from the shock of the Akeidah news. In one explanation it signals her grief; in another, 'ויהיו' means a 'הויה חדשה' — a new, altered span of life: Sarah's allotted lifespan was meant to be longer than 127 years, but the terrible news cut it short. The doubled 'שני חיי שרה' then teaches that although her death was premature, the years she did live were complete and whole ('שָׁלְמָה שני חייה').