1 Kings 13:5 - Clarke's commentary and critical notes on the Bible

The altar also was rent, and the ashes poured out from the altar, according to the sign which the man of God had given by the word of the LORD. The altar was also rent - It split or clave of its own accord; and, as the split parts would decline at the top from the line of their perpendicular, so the ashes and coals would fall off, or be poured out.