Genesis 4:1

(1) והאדם ידע AND THE MAN KNEW already before the events related above took place — before he sinned and was driven out of the Garden of Eden. So, also, the conception and birth of Cain took place before this. Had it been written, וידע אדם it would imply that after he was driven out children were born to him (Genesis Rabbah 22:2). קין — She called him so with reference to her use of the word. ה‘ — ;את קניתי is like ‘עם ה “with the Lord”; she meant to say: when He created me and my husband He created us by Himself, but in the case of this one we are copartners with Him (cf. Niddah 31a). את קין… את אחיו את הבל —The threefold ‘את’ signify extension of the scope of the text, teaching that a twin sister was born with Cain, and that with Abel two were born; consequently the text states ותוסף “and she bore more’’ than the previous time (Genesis Rabbah 22:3).

וְהָ֣אָדָ֔ם יָדַ֖ע אֶת־חַוָּ֣ה אִשְׁתּ֑וֹ וַתַּ֙הַר֙ וַתֵּ֣לֶד אֶת־קַ֔יִן וַתֹּ֕אמֶר קָנִ֥יתִי אִ֖ישׁ אֶת־יְהֹוָֽה׃

And the man knew Ḥavva his wife; and she conceived, and bore Qayin saying, I have acquired a manchild from the Lord.