Numbers 4:13

4:13 Also, they must take away the ashes from the altar ¹  and spread a purple cloth over it.

Numbers 10:18

Journey Arrangements for the Tribes

10:18 The standard of the camp of Reuben set out according to their companies; over his company was Elizur son of Shedeur.

[4:13]  ¹ tc The Greek text has “and he must place the cover upon the altar” instead of “and they must take away the ashes from the altar.” The verb is the Piel form; its nuance seems to be privative, i.e., stating that the object is deprived of the material – the ashes are removed. This is the main altar in the courtyard.