זוהר בראשית — דף קלו ע”ב

Rabbi Yitzhak asks why it is stated that Isaac was forty years old when he took Rebecca, and explains that Isaac is included in north and south, fire and water, and that Jacob was born to Isaac at sixty, whole. The text then asks why “daughter of Bethuel the Aramean, of Paddan-aram, sister of Laban the Aramean” is mentioned, and answers that Rebecca lived among wicked people without acting as they did, and that even at the age of three she did all that is told for the servant. Rabbi Yitzhak likens her to a lily among thorns: Isaac is severe judgment and she is gentle, and without her the world could not bear his judgment; so the Holy One, blessed be He, forms couples, one strong and one gentle.