פּירוש אויף בראשית 12:14

ויהי כבא אברם מצרימה AND IT CAME TO PASS WHEN ABRAM WAS COME INTO EGYPT —It should have said, “when they were come into Egypt”; but the use of the singular teaches us that he hid her in a chest, and when they demanded the custom dues they opened it and discovered her (Genesis Rabbah 40:5).

ויהי כבוא אברם מצרימה, As soon as Avram came to Egypt, etc.;” according to the plain meaning of the text, it sounds as if all the people in the entourage are considered as merely as an appendage to Avram, his fate dominating what would happen to all the people who had traveled to Egypt with him. Further confirmation of this approach to the text is what we read in verse 10 where Avram is described as descending to Egypt in the singular, i.e. וירד אברם מצרימה, which sounds as if he alone had traveled to Egypt, although we know that Lot was with him.

ויראו המצרים, all of them, when looking at Sarai, entertained the very thoughts Avraham had anticipated.