NAMES ON THE SHOHAM STONES
שמות פרק כח, י: שִּשָּה מִּשְמֹתָּם עַל הָּאֶבֶן הָּאֶחָּת וְאֶת-שְמֹות הַשִּשָּה הַנּוֹתָּרִּים עַל-הָּאֶבֶן הַשֵּנִּית כְתֹולְדֹתָּם:
מסכת סוטה דף לו/א: שתי אבנים טובות היו לו לכהן גדול על כתיפיו אחת מכאן ואחת מכאן ושמות שנים עשר שבטים כתוב עליהם ששה על אבן זו וששה על אבן זו שנאמר ששה משמותם על האבן האחת וגו' שניה כתולדותם ולא ראשונה כתולדותם מפני שיהודה מוקדם
The Aifod was worn across the front chest and the back of the Cohen and was tied by the shoulders with a special stone on each shoulder. The special stones were square shaped, set into a gold setting. And on these two stones were written all the names of the children of Yaacov. Six names were on one stone and six others were on the other stone. From the word כתולדתם in the verse, we learn that on the second stone all the names were written according to the birth order (note that this follows Rashi and not the Rambam), as follows:
יהודהגדראובןאשרשמעוןישכרלויזבלןדןיוסףנפתליבנימיןOn the first stone, five of the names were written in their birth order. However, the name of Yehudah was written first (out of order). Some explain that Yehudah was placed first, out of honor to the line of Kingship. Rabbi Epstein does not agree since Levi (servants of G-d) and Yissachar (taught Torah), should have also received preference. Rather, Yehudah received preference since that name wholly contains the name of HaShem.
Talmud Yerushalmi (Sotah) posits that the name of Binyamin was divided between the two stones, בנ on the first stone and ימין on the second stone, to fulfill the words of the verse משמתם, “from” their names but not from all their entire names (intact). However, we do not rule according to this Yerushalmi. As we see, in another law regarding the Sefer Torah, that a long name such as כדרלעומר is not written on two lines in the Torah, since it is really one name, this requires placement on one line.
HESECH HADAAS IN TEFILLIN
שמות פרק כח, לח: וְהָּיָּה עַל-מִּצְחֹו תָּמִּיד
מסכת יומא דף ז/ב: הא כתיב תמיד ההוא תמיד שלא יסיח דעתו ממנו כדרבה בר רב הונא דאמר רבה בר רב הונא חייב אדם למשמש בתפיליו בכל שעה ושעה ק"ו מציץ
The Tzitz has only one holy name in it and yet one needs to be consistently aware of wearing it, then even more so for Tefillin which has many holy names in it. Evidently, the main concern is for frivolity when wearing Tefillin, since this ruling is only from the Rabbis, thus, the only concern is in a case of profaning the name of G-d (and not the general lack of awareness, which would be the concern if this concept was of Torah origin).