Cain Was Framed!
I am Cain. I was born in the Garden. My parents ate the Fruit of Knowledge, and were thrown out onto the Cold Hard Earth. They were punished with Pain and Toil, but the benefit of the Knowledge of Good and Evil more than made up for it. Their animal, semi-sentient urges had become transformed. They could now Reflect, and think about Thought, and Decide, "This desire is Selfless, I will cultivate it; That desire is Selfish, I will withstand it."
I am Cain. I did not eat the Fruit of Knowledge, but I was also Cast Out onto the Cold Hard Earth. My Younger Brother, Abel, was born with Knowledge in his Blood. He had Foresight. He had Understanding. He could Move On. Uprooted from the Ground of Eden, he became a Herder of Animals. God had put us in the Garden to Tend the Plants, so I continued the Harvest Work on the Outside.
How was I to know that the Soil was no longer an option? That I was following a Backwards, Dead-End Path?
No one told me. They didn't need to be told. No One Told Me!
I gave the Best I could Grow to God. God Didn't Want It!
Wasn't this my Purpose on Earth? How dare He accept Abel's Animals and not my Garden?!
והאדם ידע את חוה אשתו
ותהר ותלד את קין
ותאמר קניתי איש את ה׳
ותוסף ללדת את אחיו את הבל
ויהי הבל רועה צאן וקין היה עובד אדמה
And the man (or: Adam) had known Hhava, his wife;
she became pregnant, and gave birth to Qayin (Cain) —
and she said, "I have gained a man with God."
She then continued giving birth, [and had] his brother, Hevel (Abel);
and Hevel was a shepherd, while Qayin was a worker of the land.
The grammar is clear. והאדם ידע And Adam had known is pluperfect tense. Had known, not knew. The subject-noun, followed by a verb in what we call today the "past tense" form, expresses an action preceding the previous action. If it were וידע האדם in what the grammarians call the wayyiqtol form ("future" + 'flipping vav'), then it would be an action in sequence, and then Adam knew.
Or in other words, as R' Shelomo Yitzhhaqi (Rashi) commented:
This had already [occured] before the earlier narrative — before he sinned and was kicked out of Gan ‘Eiden. The same goes for the conception and birth...
So Qayin, at least, was born in the Garden. We are never told that he ate the fruit of the Tree of Knowledge of Good and Evil — and yet he was kicked out of Paradise just the same. Hevel, his younger brother, seemingly was born on the Outside, and was conceived by Adam and Hhava after having eaten the fruit. He was born with the knowledge of good and evil, of death (for on the day you eat of it you will surely die). Qayin, this verb yada‘ implies, was not. Did he even understand what death was, until he created it with his own hands?