Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 25
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 25, with English translation by Maimonides (Rambam).
לַעֲרֹךְ נֵרוֹת בַּמִּקְדָּשׁ, שֶׁנֶּאֱמָר: "יַעֲרֹךְ אֹתוֹ אַהֲרֹן וּבָנָיו" (שמות כז, כא).
To prepare the candles of the Sanctuary, as [Exodus 27:21] states: "Aaron and his sons shall prepare it."