Machatzit Hashekel ('half-shekel'): In Gematria, the Hebrew word "shekel", according to the alphabetic transformation known as Atbash, is equivalent to the letters "b’dach", which has a numerical value of 26 – the same as the Name of Hashem.
Moshe struggled to understand why the Children of Israel were commanded to donate only a half-shekel and not a whole shekel. By teaching Moshe the half-shekel, HaKadosh Baruch Hu showed him that he would not bring them into the Land and they would not merit the complete rectification; therefore, the Name of Hashem would not be "complete" immediately. Only in the future will His Name and His throne be complete.
As stated, all of this is alluded to in the closing word of Parashat Terumah and the continuation in Parashat Tetzaveh: "... nechoshet ve'ata tetzaveh": Ner (Menorah), Hodesh (month), and Shekel (half-shekel), Tir-eh (observe), and you shall command... HaKadosh Baruch Hu said to him: "From these three things I had to show you, you will learn why your name is hidden in this portion." This hints that he would be "hidden" and die, and thus the complete rectification of the People of Israel would not yet occur. It says only "And you shall command" rather than "And Hashem spoke to Moshe" to hint that he would not enter the Land and would remain hidden. (Zera Shimshon, Parashat Tetzaveh, Art. 1)
