Charles Ellicott Commentary Leviticus 6:10

"And the priest shall put on his linen garment, and his linen breeches shall he put upon his flesh; and he shall take up the ashes whereto the fire hath consumed the burnt-offering on the altar, and he shall put them beside the altar." — Leviticus 6:10 (ASV)

And the priest shall put on his linen garment.—The officiating priest was to put on his sacerdotal garments, which consisted of four pieces—namely:

1. The tunic, which was a long close robe of fine linen, with sleeves but without folds, covering the whole body, and reaching down to the feet.
2. Linen breeches—better, linen drawers—which, according to the authorities during the second Temple, reached to the knees and were fastened by ribbons above the flanks.
3. A linen girdle, which, according to the same authorities, was three fingers wide and thirty-two cubits long, and, like the veil of the court and of the sanctuary, was embroidered with figures.
4. A mitre, or better, turban, which was likewise of fine linen, and was fastened to the head by means of ribbons, to prevent its falling off (Exodus 28:4; Exodus 28:40; Exodus 29:5–10; Leviticus 8:13).

Though the second and third only are here mentioned, there can hardly be any doubt that all the four garments were meant, and that the third and fourth are either omitted for the sake of brevity, or because they are included in the first term, which is the reason why some of the ancient versions have it in the plural.

Take up the ashes which the fire had consumed with the burnt offering.—Better, take up the ashes into which the fire had consumed the burnt offering. That is, the ashes into which the consuming fire had converted the victim.

He shall put them beside the altar.—During the second Temple, a priest was appointed by lot to take off from the altar every morning at least a shovelful of ashes and carry it without the camp, and when the ashes accumulated they were entirely removed to the same place.