ואחרי כן קבר אברהם את שרה אשתו אל מערת שדה המכפלה ... (כג-יט)
The Medrash Tanchuma says that Avraham Avinu eulogized Sarah with the words of אשת חיל, and on the posuk זממה שדה ותקחהו, the Medrash explains this to be a reference to the מערת המכפלה. The obvious question is - Avraham completed the purchase, and not Sarah. Why then is she receiving the credit?
On the earlier words of our parsha, "לכל באי שער עירו" in front of all the townspeople; Rashi says that everyone came to pay their respects to Sarah and be gomel chessed to her. Presumably they had been recipients of goodness from Avraham and Sarah. It’s therefore no wonder that they initially offered a burial plot pro-bono, all in her zechus. Thus, "זממה שדה" she orchestrated and pulled the strings through her good deeds of the past and now she received her just and well-deserved reward.
There is a profound pshat from the Slonimer Rebbe zt”l on the aforementioned Medrash. On the verse "לא תירא לביתה משלג כי כל ביתה לבוש שנים" - She need not fear Gehinom because she has shanim, reading it as shnayim - two. Two mitzvos protecting her - Shabbos and Bris Milah. The mitzvah of Shabbos we can readily comprehend, but what did she have to do with mitzvas milah? He answers both questions with the following beautiful thought. Many a time it is the zechusim of the נשים צדקניות our nshei chayil that enable the menfolk to fulfill mitzvos. The reward is thus in their merit. So even though they don’t actually relate to the Milah, they receive credit for it. Similarly, although she already passed away, the ability to acquire the field was in her merit. Therefore, although Avraham concluded the physical sale, the posuk aptly says "זממה שדה" she truly accomplished it. This מחשבה reminds me of one the Zaida would often say; but with a twist. The Torah, at times, refers to a woman as שְאֵרוֹ, his close relative. Why? It’s possible to suggest that שְאֵרוֹ could mean leftovers. Implying that even after death, the aura of a niftar remains with us and we can still enjoy their ‘leftovers’. May all our illustrious forbears be melitzei yosher for us.