Scripture says that she became his wife after he brought her into his mother's tent.
Genesis 24:67
67 Then Isaac brought her into the tent of Sarah his mother and took Rebekah, and she became his wife, and he loved her. So, Isaac was comforted after his mother’s death.
Scripture informs us that Isaac was around 37 years old when his mother Sahar died, and after Sahar's death Isaac took his mother's tent to live in.
When Isaac was 40 years old, his father, Abraham, gave Rebekah to him, to become Isaac's wife.
Isaac was possibly around 30-33 years old when he went with Abraham to be sacrificed to God by his father. Isaac did not go back 'home' with Abraham and the bible is silent as to whether or not he went to see his mother after this event. Some 7 or so years later she died and then after another 3 years Rebekah is given to Isaac as a wife for him by his father Abraham who had sent his servant to find a wife for him from among Abraham's brother, Nahor's, family.
The Bible also tells us that Terah, Abraham and Sarah's father had died probably 1 year before Sahar's death and that Nahor, Abraham's brother had probably sent a servant to Abraham with this news as well as news about his descendant family
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