שמות פרק יג , טז וְהָּיָּה לְאוֹת עַל-יָּדְכָּה וּלְטוֹטָּפֹת בֵין עֵינֶׂיך
מסכת מנחות דף לד/ב ת"ר לטטפת לטטפת לטוטפת הרי כאן ד' דברי רבי ישמעאל ר"ע אומר אינו צריך טט בכתפי שתים פת באפריקי שתים
Tosefos and others strive greatly to explain how the word טטפת relates to Tefillin. Rabbi Epstein wonders why they just don’t explain simply. This word refers to the beauty that is upon the head, which are Tefillin.
Tosefos Yom Tov states that the 4 parshios within the Tefillin are all required; lacking any one of them fails to enable fulfillment of the mitzvah. However, he states that the source for this law is not found in Talmud.
Rabbi Epstein posits that the understanding of the above is based on another derivation regarding the word שעטנז requires being combed, spun and woven, since all written (alluded) together in one word (שוע טווי נוז). The same can be applied to Tefillin since the 4 parshios are all written (alluded) together in the one word טטפת (two and two).
