HaLevi on God's Ineffable Name

וְכֵן יִחֵד אוֹתָנוּ בְּאָמְרוֹ: 'ה' בָּדָד יַנְחֶנּוּ וְאֵין עִמּוֹ אֵל נֵכָר'. וְהָיָה הַשֵּׁם הַזֶּה מְיֻחָד בָּנוּ שֶׁאֵין אַחֵר יוֹדֵעַ אוֹתוֹ אֲמִתַּת יְדִיעָתוֹ זוּלָתֵנוּ. וְהוּא שֵׁם נוֹדָע, לֹא יִסְבֹּל הֵא הַיְדִיעָה כַּאֲשֶׁר הִיא נוֹסֶפֶת עַל אֱלֹהִים, וְיֵאָמַר: הָאֱלֹהִים. וְהַשֵּׁם הַזֶּה מִכְּלָל הַמַּעֲלוֹת הַטּוֹבוֹת אֲשֶׁר יֻחַדְנוּ בָהֶם, וְסוֹדוֹ נִסְתָּר.

The Tetragrammaton is a name exclusively employable by us, as no other people knows its true meaning. It is a proper name which takes no article, as is the case with Elohim in the form hāelōhim. It belongs, therefore, to the prerogatives by which we are distinguished. Although its meaning is hidden, the letters of which it is composed speak. For it is the letters alef, hē, wāv and yōd which cause all consonants to be sounded, as no letter can be pronounced as long as it is not supported by one of these four, viz. a by alef, and hē, u by wāv, and i by yōd. They form, so to speak, the spirit in the bodies of the consonants.