Albert Barnes Commentary Ezekiel 43:15

"And the upper altar shall be four cubits; and from the altar hearth and upward there shall be four horns." — Ezekiel 43:15 (ASV)

The altar ... the altar - See the margin. The two words may denote, the first a square block (N) placed upon the upper settle, the second a slab (O), the thickness of which is not given, from which rose four horns (Exodus 27:2); and to which it seems probable that the victims of sacrifice were at times bound (Psalms 118:27).

Why the names Harel and Ariel were used must be conjectural. Mount of God may have been a title naturally given to the place of sacrifice, as elsewhere to the place of worship (Ezekiel 40:2); Lion of God was a term used for the Holy City itself (Isaiah 29:1).