How many children did Adam and Eve have, how long did they stay in the Garden of Eden, and who was Cain's wife?
The Old Testament does not tell us how many children Adam and Eve had. Scripture mainly focuses on the males which are born to a set of parents. There is a previous question titled, “Where did Cain’s wife come from?” that talks about the children of Adam and Eve.
The Garden. Genesis 3:22-23 tells us that God removed Adam and Eve from the garden of Eden after they sinned.
. . . now, lest he stretch out his hand, and take also from the tree of life, and eat, and live forever”– therefore the LORD God sent him out from the garden of Eden, to cultivate the ground from which he was taken. So He drove the man out; and at the east of the garden of Eden He stationed the cherubim, and the flaming sword which turned every direction, to guard the way to the tree of life. Now the man had relations with his wife Eve, and she conceived and gave birth to Cain, and she said, “I have gotten a manchild with the help of the LORD.” (NASB) Genesis 3:22-4:1
God also set a cherubim to keep them from coming back. Apparently, Adam and Eve were not in a hurry to have children until Genesis 4:1. Scripture does not tell us how long Adam stayed in the garden. If Eve had given birth to Cain before the fall, then we could guess that Adam and Eve might have been in the garden at least 16 years since Cain might have been married. But scripture gives us no clue as to how long they were in the garden.
Cain’s Wife. Scripture does not tell us who Cain’s wife is either. He would have had to marry one of his sisters. All that scripture says in Genesis 4:17 is:
And Cain had relations with his wife and she conceived, and gave birth to Enoch; and he built a city, and called the name of the city Enoch, after the name of his son. (NASB) Genesis 4:17
It is amazing what scripture does not talk about. It does not give us a manual on raising children, financial planning, or some current topic. God does not reveal everything to us in scripture. He has chosen to reveal those things that are important. The goal of scripture is to tell us about God. The Old Testament points forward in time to Jesus. The gospels of the New Testament look right at Jesus, while the rest of the New Testament looks back in time to Jesus.
Reference Links:Where did Cain's wife come from?
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