In Genesis 3, Adam is told that the GROUND is cursed, and he will RETURN to it.
In Genesis 4, Cain is told that HE is cursed FROM the ground; the GROUND accepted Abel, but it REJECTS Cain.
Perhaps the ground is humanity, and Cain has cut himself off from it. A vagabond.
To Adam he said, “Because you listened to your wife and ate fruit from the tree about which I commanded you, ‘You must not eat from it,’
“Cursed is the ground because of you;
through painful toil you will eat food from it
all the days of your life.
It will produce thorns and thistles for you,
and you will eat the plants of the field.
By the sweat of your brow
you will eat your food
until you return to the ground,
since from it you were taken;
for dust you are
and to dust you will return.”
Genesis 3:17-19 (NIV)
Now you are under a curse and driven from the ground, which opened its mouth to receive your brother’s blood from your hand.
Genesis 4:11 (NIV)