"In the Tent of Meeting, outside the veil" (Exodus 27:21). The Menorah did not need to be placed anywhere except within the veil, beside the Ark; yet it is set outside the veil, to make known to you that He does not need light. And why did He tell you to do it? In order to give you the merit of the light. Another interpretation: in the way of the world, a king of flesh and blood makes himself a bed and a table, and he places the lampstand to his left. But in the Temple it is not so; rather, the Menorah was placed to the right of the table, to make known to you that He does not need light from what is yours. And why did He tell you? To give light to you in the World to Come, when darkness comes upon the nations of the world, as it is said, "For behold, darkness shall cover the earth" (Isaiah 60:2).
The Lamp Set Outside the Veil and Its Promise
Yalkut Shimoni on Torah 378:4
בְּאֹהֶל מוֹעֵד מִחוּץ לַפָּרֹכֶת לֹא הָיְתָה הַמְּנוֹרָה צְרִיכָה לְהִנָּתֵן אֶלָּא לִפְנִים מִן הַפָּרֹכֶת אֵצֶל הָאָרוֹן, וְהִיא נְתוּנָה מִחוּץ לַפָּרֹכֶת לְהוֹדִיעֲךָ שֶׁאֵינוֹ צָרִיךְ אוֹרָה, וְלָמָּה אָמַר לְךָ, כְּדֵי לְזַכּוֹתְךָ לְמָאוֹר. דָּבָר אַחֵר. בְּנֹהַג שֶׁבָּעוֹלָם, מֶלֶךְ בָּשָׂר וָדָם עוֹשֶׂה לוֹ מִטָּה וְשֻׁלְחָן, הוּא נוֹתֵן הַמְּנוֹרָה מִשְּׂמֹאלוֹ, אֲבָל בְּבֵית הַמִּקְדָּשׁ אֵינוֹ כֵּן, אֶלָּא הַמְּנוֹרָה הָיְתָה נְתוּנָה מִימִינוֹ שֶׁל שֻׁלְחָן לְהוֹדִיעֲךָ שֶׁאֵינוֹ צָרִיךְ אוֹרָה מִשֶּׁלְּךָ, וְלָמָּה אָמַר לְךָ, לְהָאִיר לְךָ לָעוֹלָם הַבָּא כְּשֶׁתָּבוֹא חֲשֵׁכָה עַל אֻמּוֹת הָעוֹלָם, שֶׁנֶּאֱמַר (ישעיה ס, ב) "כִּי הִנֵּה הַחֹשֶׁךְ יְכַסֶּה אֶרֶץ" וְגוֹ'.