Where did Cains wife come from and also the other people?
The events surrounding the death of Abel by his brother Cain can be found in Genesis 4:1-15. This question is directed at the events after Abel’s death, after God protected Cain with a sign. We do not know what the sign was but it must have been significant. After Cain received the sign, the scriptures say Cain had sexual relations with his wife.
