Question: Where did Cain get his wife? If she was Adam and Eve's wasn't this incest. Isn't incest a sin?

Answer: Adam and Eve were the first two people that God created (Genesis Chapters 1-2). All of the human race descended from them. Adam named his wife Eve, because she would become the mother of all the living. (Genesis 3:20, NIV) So, yes, everyone on the planet was/is related. All of Adam & Eve's children had no choice but to marry their brothers and sisters -- they were the only ones around. And, for-the-record, Adam and Eve had plenty of time to have many other sons and daughters. After Seth was born, Adam lived 800 years and had other sons and daughters. (5) Altogether, Adam lived 930 years, and then he died. (Genesis 5:4-5, NIV) The question as to "was this incest?", well yes! That is, by our current and recent historical standards. A dictionary definition of incest is as follows... Incest. n. Sexual intercourse between persons so closely related that marriage between them is forbidden by law or taboo. (Funk & Wagnalls Standard Desk Dictionary) So, in fact, it was truly only incest if it was forbidden 'by law or taboo' for them to marry. The issue here is what was morally (and legally) correct at that time. God is the absolute law maker (and was actually the only Law maker back in the beginning). The Bible (God's Word) shows us that there was no prohibition to marriage of close relatives until quite some time after creation. And this does make sense. Every rule God has established is based upon one of two things... (1) His holiness, or (2) His want to protect us from harm. Regarding the first, anything that opposes, or falls short of, the absolute standard of God's holiness is sin (Romans 7:7, 1 John 3:4). These things are unchangeable forever because God, Himself, cannot change (Malachi 3:6, Hebrews 13:8). Beyond those, God out of His love for us established at various times laws and regulations to protect us. God can, and has, legitimately changed these at various times. For example consider the dietary rules in the Old Testament that were removed in the New (but this is a different topic). Incest laws fit into this category as well. Consider some of the reasons why incest is harmful now. A major one is that the intermarriage of close blood relatives substantially increases the risk of genetic defects. In fact, in humankind as a whole genetic problems are increasing. As a species, man's DNA is breaking down over successive generations. This makes sense in regards to Creation and the Fall. The effects of sin that started at the fall have affected all aspects of creation (Romans 8:19-22). Things are growing worse (Hebrews 1:10-12). Adam and Eve's DNA would have been perfect, when created. Each subsequent generation then began to see increased mutations and defects -- likely compounding the farther away from the beginning man got. God did not restrict marriage within a family at the beginning. In fact, it was assumed when he told people to be fruitful and multiply (Genesis 1:27-28). Even to the time of Abraham and Sarah it appears to be common and acceptable, and again there was no prohibition from God. Abraham replied, "I said to myself, `There is surely no fear of God in this place, and they will kill me because of my wife.' (12) Besides, she really is my sister, the daughter of my father though not of my mother; and she became my wife. (Genesis 20:11-12, NIV) It was only in the giving of the Law (at the time of Moses) that God instituted a number of rules to protect His people. Incest was one of them... "`If a man marries his sister, the daughter of either his father or his mother, and they have sexual relations, it is a disgrace. They must be cut off before the eyes of their people. He has dishonored his sister and will be held responsible. (Leviticus 20:17, NIV) "`No one is to approach any close relative to have sexual relations. I am the LORD. (7) "`Do not dishonor your father by having sexual relations with your mother. She is your mother; do not have relations with her. (8) "`Do not have sexual relations with your father's wife; that would dishonor your father. (9) "`Do not have sexual relations with your sister, either your father's daughter or your mother's daughter, whether she was born in the same home or elsewhere. (10) "`Do not have sexual relations with your son's daughter or your daughter's daughter; that would dishonor you. (11) "`Do not have sexual relations with the daughter of your father's wife, born to your father; she is your sister. (12) "`Do not have sexual relations with your father's sister; she is your father's close relative. (13) "`Do not have sexual relations with your mother's sister, because she is your mother's close relative. (14) "`Do not dishonor your father's brother by approaching his wife to have sexual relations; she is your aunt. (15) "`Do not have sexual relations with your daughter-in-law. She is your son's wife; do not have relations with her. (16) "`Do not have sexual relations with your brother's wife; that would dishonor your brother. (17) "`Do not have sexual relations with both a woman and her daughter. Do not have sexual relations with either her son's daughter or her daughter's daughter; they are her close relatives. That is wickedness. (Leviticus 18:6-17, NIV) (See also Deuteronomy 27:22) Truly, by this time, it was surely necessary. The shortened life-spans, and number of generations removed from Adam, both testify that increased genetic problems would have made continuing such practices harmful. Even more so today. But as to the time frame prior to then, did Cain, or even Abraham, sin in marrying a sister? No! From the giving of the law to now, God has not changed his restrictions on the practice of incest -- in fact, New Testament warnings regarding being sexually immoral are based upon these standards (See Ezekiel 22:11, 1 Corinthians 5:9-11; 6:9, Hebrews 13:4, Revelation 21:8, etc). This taboo has even been intertwined within the fabric of most of the world -- a world that has been historically influenced by Christianity. To break any command or instruction given by God is sin. So, as for the present, would anyone marrying a sister or brother be sinning now? Definitely yes!