וַאֲבִימֶ֕לֶךְ לֹ֥א קָרַ֖ב אֵלֶ֑יהָ וַיֹּאמַ֕ר אֲדֹנָ֕י הֲג֥וֹי גַּם־צַדִּ֖יק תַּהֲרֹֽג׃
Авимелех не приблизился к ней; и сказал он:'Господи, убьёшь ли ты даже праведный народ?
Rashi
לא קרב אליה HE HAD NOT COME NEAR HER — The Angel prevented him, as it is said (v. 6) “I have not permitted thee to touch her” (cf. Genesis Rabbah 52).
Chizkuni
ואבימלך לא קרב אליה, “while Avimelech had not become intimate with her.” [but he had kidnapped her, Ed.] The reason why the Torah had to emphasise this latter point, i.e. that Avimelech had not violated Sarah sexually, is the fact that her being kidnapped occurred so close to her becoming pregnant with Yitzchok.
Ibn Ezra
Will You also kill an innocent nation. He prayed on behalf of his entire nation.