Kommentar zu Bereschit 30:8

נפתולי אלהים WRESTLINGS OF GOD — Menachem ben Seruk explains in his Machbereth (Dictionary) that the word נפתולי is of the same root as פתיל in (Numbers 19:15) “a covering (פתיל) closely bound upon it”, so that the words here mean: By bonds from God have I been joined to my sister (made equal to her) to merit the privilege of having children. I, however, explain it in the same sense as (Deuteronomy 32:5) “perverse and crooked (עקש ופתלתול)”. I have been persistent and have made many importunities and wrestlings with God that I may become like my sister.

נפתולי אלוקים נפתלתי, this formulation is partly due to literary considerations, so that the letter נ at the beginning of the word נפתולי is due primarily in order to match the latter נ in the word נפתלתי. We encounter something similar is the construction of Samuel I 20,28 נשאל נשאל דוד,

נפתלי אלוהים נפתלתי, the word נפתולי is a variant of the word פתיל as in צמיד פתיל, a tightly fitted lid (Numbers 19,15) Rachel meant that her cleaving to her husband was an attachment containing spiritual, religious dimensions, making the bond between them immeasurably stronger.