Zitat Kommentar zu Schir haSchirim 7:4

It shall be healing for your navel Heb. לשרך. The wisdom shall be healing. שרך is like (Song 7:4): שררך, which means, your navel.

ויאמר ה׳ לה, G'd said to her, etc. Although this verse has been explained by many there is still no truly satisfactory answer. G'd responded to her fear that she would miscarry by explaining to her that there was nothing medically wrong in her womb but that she was carrying two instead of merely one fetus. Whereas normally, when a mother expects twins, the two fetuses get along inside the womb (compare Song of Songs 7,4), in Rebeccah's case they did not. Hence her feeling of being crushed. She did not merely carry twins but each one was destined to become a nation with very different characteristics from one another. Not only would each one be a king in his own right, but these respective nations would endure for thousands of years. All of this would not have resulted in her having a feeling of being crushed were it not for the fact that these twins did not conform to the usual pattern of twins. When G'd explained that ממעיך יפרדו, "they will be totally separate already while still inside of you," this meant that they would not only be separate inside of Rebeccah but their being separate would continue after they were born. At any rate, G'd reassured Rebeccah that there was nothing wrong with her womb.