Upon the top of the mountain. — Comp. Ezekiel 40:2. The command to keep and observe everything is closed, as often in similar cases, by a summary statement of the reason: for the whole surroundings of the dwelling-place of the Most High are holy.
With Ezekiel 43:13 a new part of the vision begins, extending to the close of Ezekiel 46, describing the new ordinances of the sanctuary. This is fitly opened with a description of the altar for the sacrifices, the central act of the ancient worship.