Genesis 4:16-26
King James Version (KJV)
16 And Cain went out from the presence of the Lord, and dwelt in the land of Nod, on the east of Eden.
he got his wife from the land of Nod most likely just as its is written here.
17 And Cain knew his wife; and she conceived, and bare Enoch: and he builded a city, and called the name of the city, after the name of his son, Enoch. (I do not know if this is the same Enoch that was righteous : I don't think so.),
The land was named after Nod. Who was Nod and where did he come from ? There is one place I believe he came from that is the 6th day creation .
Genesis 1:
26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
here we have man being created a full day, before Adam and Eve were ever created.
27 So God created man in his own image, in the image of God created he him; male and female created he them.
28 And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.
He told them to be fruitful and multiply and replenish the earth.
29 And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree yielding seed; to you it shall be for meat.
30 And to every beast of the earth, and to every fowl of the air, and to every thing that creepeth upon the earth, wherein there is life, I have given every green herb for meat: and it was so.
31 And God saw every thing that he had made, and, behold, it was very good. And the evening and the morning were the sixth day.
You see it was the Sixth day. God rested the Seventh , then the day After the day of rest: He created Adam and Eve .
Nod was named after those Sixth day people's and it is highly likely that is where Cain got his wife from. Not from Adam & Eve's daughters.