C. F. Keil and Franz Delitzsch on Leviticus 6:8

Lev 6:8

(Hebrew_Bible_vv_1-6). The Law of the Burnt-Offering commences the series, and special reference is made to the daily burnt-offering (Exo 29:38-42).

“It, the burnt-offering, shall (burn) upon the hearth upon the altar the whole night till the morning, and the fire of the altar be kept burning with it.” The verb תּוּקד is wanting in the first clause, and only introduced in the second; but it belongs to the first clause as well. The pronoun הוא at the opening of the sentence cannot stand for the verb to be in the imperative. The passages, which Knobel adduces in support of this, are of a totally different kind. The instructions apply primarily to the burnt-offering, which was offered every evening, and furnished the basis for all the burnt-offerings (Exo 29:38-39; Num 33:3-4).