Kabbalah sobre Génesis 25:23

"And Hashem said to her, 'Two nations are in your womb, and two peoples'" (Gen. 25:23). These are the two proud ones, the liver and the heart. Rabbi Yosi said that these are the brain and the heart, but Rabbi Yehuda said, The brain is not included in this, for it is written, "in your womb (lit. 'belly')," and the brain is not in the belly, but in the head. "And two peoples from your bowels and the elder (lit. 'great') shall serve the younger." This is the liver, which is great and big, and which serves the heart, as Rabbi Yehuda said, The liver receives the blood, and serves it to the heart!