תפילין >> אֶתְפָּאָֽר
And He said to me, "You are My servant, Israel, about whom I will boast." וַיֹּ֥אמֶר לִ֖י עַבְדִּי־אָ֑תָּה יִשְׂרָאֵ֕ל אֲשֶׁר־בְּךָ֖ אֶתְפָּאָֽר
Daily Zohar - Bo Day 4
Based on Zohar Shemot 43A
"And it shall be for a sign upon your hand, and for frontlets between your eyes". (Ex. 13:16) This commandment is considered in a different fashion, since it is not considered[only] a commandment but [also] a matter of holiness [for the parchments within them are the secret of mochin and are called 'holy']. And these [signs and frontlets – Ed.] are the Tefilin — the hand Tefilin and the head Tefilin, for they are a rectification of glory and splendor of variegated supernal colors. Therefore they are called "frontlets" [lit. adornments] as is written: "Israel, in whom I will be glorified". (Isaiah 49:3)
http://www.chabad.org/kabbalah/article_cdo/aid/1395937/jewish/Daily-Zohar-Bo-Day-4.htm