מדרש על שמואל ב 5:22

... Teach us, oh master – may one light a lamp for personal use from the Channukah lights? Our masters taught us – R’ Acha said in the name of Rav ‘it is forbidden to light a lamp to use from the Channukah lights, but one may light a Channukah light from a Channukah light.’ From where did they learn that it is permissible to light a Channukah light (from it)? R’ Yaakov ben Aba said, they learned it from the menorah that was in the Holy of Holies, as our rabbis taught that if one found they had gone out, they should be cleaned out and re-lit from those that are still lit. (Tamid 3) If we would relight an extinguished lamp of the menorah, which was placed in the innermost sanctum, from the lamps still burning all the more so it is permissible to light a Channukah light from the lights still burning.’ The Holy One said, just as in this world lamps were lit in the Holy of Holies, so too I will do when I rebuild Jerusalem. From where do we know this? From the words of the prophet “And it shall come to pass on that day, that I will search Jerusalem with candles…” (Tzephaniah 1:12)