Shevuos 35b: The Rabbis learned: Any letter attached to a Divine Name, whether as a prefix or a suffix, may be erased. Others say: A suffix may not be erased, for the Name has already sanctified it. Rav Huna said: The halacha follows the Others.

שבועות לה: ת״ר: כל הטפל לשם בין מלפניו ובין מלאחריו ־ ה״ז נמחק וכו’ אחרים אומרים: לאחריו אינו נמחק, שכבר קדשו השם. אמר רב הונא: הלכה כאחרים.

The Torah says, “And you who cling to Hashem your G-d are all alive today” (Devarim 4:4). The Ohr Hachaim Hakadosh comments that the Four-Letter Name of Hashem can only have a prefix, never a suffix. Therefore, one might have thought that the Jewish people, although they may cling to Hashem, are not permanently with Him; they can be erased, Heaven forbid. Therefore the Torah says, “You who cling to Hashem your G-d” (א-להיכם) with the suffix attached, to show that we are like the suffix: Hashem has made us holy and we can never be erased.

Thus the Torah’s blessing to the tzaddikim is the exact inverse of the curse “may his name be erased.” The tzaddikim cling to Hashem in this world and in Olam Haba and their names are never erased.