The flame was strong, unlike a conventional flame. Therefore, the water could not extinguish it. Although the copper altar was located in the yard under the open sky, rain never flooded it. (Moshe Weissman, “The Midrash Says,” Chapter “Tzav.”)
The burning of the will to receive is the strongest possible corrective action.
There are various types of correction: the four types of executions (plagues), flaying, salting, koshering and correct consumption, the so-called three years of eagle (for fruit-bearing trees), seven years of plowing, etc. In other words, various types of egoism require special kinds of correction.
The heaviest egoism needs the strongest correction, by fire. When we work at a level of self-immolation and sacrifice our ego for the sake of correction in the future, there are no obstacles on our way.
It is said that water was not capable of putting out the flame. This fact emphasizes that correction by fire is much higher than any other ways of self. The water itself is cleansing, purifying, but it is less powerful than cleansing by fire.
The water corrects only to the level of bestowal, Hafetz Hesed (Galgalta ve Eynaim), whereas the fire corrects the very intention, to receive for the sake of others.
From KabTv’s “Mysteries of the Eternal Book”, 12/6/2013