Shalom. I was reading this week’s parshah ( Genesis 18:1 – 22:24 ) and noticed the Torah uses the word Pechad rather than Zechor in Remembering Sarah. When one compares the uses of of the two words, as related to all the matriarchs of Israel, (Sarah, Rachel, Leah, Rivka, Channah, et. al.) it singles out Sarah for special attention by the word “pechad” as opposed to the word “zechor”.
Rashi comments that remembered is related to “and Avraham Prayed” for the needs of Abimelech before the needs of his own house so he was heard before the healing of Abimelech’s house – What’s Bothering Rashi – Vayeira
Pechad – “remembered”, to account for, to reckon, muster (as in a roll call) Exodus 3.16, Numbers 1.44. Not as in zechor – remembered, but as in what was PROMISED to Avinu Avraham in the COVENANT between the parts …. this is related to “the saying” or OATH of HaShem – “so shall thy seed be” Genesis 15.5
Contrasting the “remembering” Pechad of Sarah with that of remembering Zechor Rachel, the accounting of Sarah’s innocense in the matter of Abimelech is a special type of remembering – a one time accounting of all the seed of Jacob in innocense, according to the COVENANT between the parts.
Fortunately, we are given “hind-sight” into Genesis 15 “and shall serve them four hundred years and afterwards they shall come out with great substance” from Exodus 3.16 pechad pechadti “surely I have remembered you AND seen all that is done to you in Egypt.” perfect past tense. Exodus 2.24, 25
Rashi relates that the remembering of Sarah by HaShem is perfect past tense. Rashbam relates that the “test of Avraham” (the Akeida) was “a punishment” for Avraham making a covenant with Abimelech since Avraham’s descendants were commanded to utterly destroy the inhabitants of Canaan (who were sacrificing their infants in fertility rites – leading to the Jewish dietary laws of Kashruth, further setting apart as holy the children of Jacob…).
I think the covenant Avraham made with Abimelech was because Avraham “preached the fear of HaShem” to Abimelech and because HaShem visited in a dream (& healed) the house of Abimelech – Brashith (Genesis) 20.11 because in faith, Avinu Avraham recognized HaShem’s hand in all these events!