That which the verse states: “The Lord is desirous of him because of his righteousness; he will render the Torah great and glorious” (Isaiah 42:21). The Holy One blessed be He said to Moses: ‘It is not because I need the lamps that I cautioned you regarding the lamps, but rather to accord them merit,’ as it is stated: “And the light rests with Him” (Daniel 2:22), and it is written: “Even darkness does not darken for You, and night, like day, illuminates.
Darkness and light are the same” (Psalms 139:12). It comes to teach you that He does not need the lamps of flesh and blood. Know that when a person builds a house, he crafts windows that are narrow from without and wide from within. Solomon, who built the Temple, did not do so, but rather, he crafted windows that are narrow from within and wide from without, so that the light would emerge from the Temple and illuminate outside, as it is stated: “He made for the House recessed narrowing windows” (I Kings 6:4).
This is to inform you that He is all light and does not need their light. Why, then, did He command you? It is to accord you merit. That is why it is stated: “When you kindle the lamps.”
That is, “The Lord is desirous of him because of his righteousness.” Moreover, [God said:] ‘If you are vigilant in kindling the lamps before Me, I will illuminate for you with a great light in the future.’ That is why it is stated: “Arise, shine, for your light has come…. Nations will walk by your light and kings by the radiance of your shining” (Isaiah 60:1, 3).