Why was Noach ordered to build an enormous ark, if it in any event would be unable to accommodate every species without a miracle?
The Ramban, in his commentary to Parashat Noach (6:19), addresses the obvious question of how the ark constructed by Noach could possibly have accommodated a pair of every species of animal on earth. The ark was indeed quite large, but certainly not large enough to house two of every species, particularly given that many animals are themselves very large. The Ramban writes that undoubtedly the animal kingdom's refuge in the ark was of a miraculous nature; a pair of every species fit inside the ark in defiance of the laws of physics, in order to ensure the survival of all creatures on earth.
Of course, this conclusion raises the question of why an ark was necessary in the first place. Or, at very least, as the Ramban asks, God should perhaps have instructed Noach to construct a small-sized vessel so as to maximize the great miracle of the animals' salvation. Why was Noach ordered to build an enormous ark, if it in any event would be unable to accommodate every species without a miracle? The Ramban initially suggests that this project was perhaps intended as a means of drawing the people's attention to the ark, which could potentially have had the effect of inspiring the generation to repent. Alternatively, the Ramban writes, God's command concerning the ark reflects His general tendency to minimize supernatural phenomena, to perform miracles through only minor deviations from the natural order. God ordered Noach to construct a large ship so as to limit the extent to which the animals would require a miracle to find space on the ark.
Rav Chayim Elazary, in his work Shevilei Chayim (Canton, 1947), offers a beautiful insight to enhance our appreciation of the precise role of the ark and to explain why God chose specifically this means of rescuing Noach and the animal kingdom. Ever since the second generation of mankind – Kayin and Hevel – relations among people have been characterized by envy, greed and violence. As Rashi (6:13) famously cites from the Gemara (Sanhedrin 108a), the sentence against the generation of the flood was issued specifically on account ofchamas – violent theft. The ongoing prevalence of thievery and violent struggle between individuals and clans, which began already in the earliest chapters of human history, could lead one to believe that such is the inescapable lot of mankind, that people – like animals – will forever be engaged in incessant and bitter conflict.
To dispel this disheartening notion, God saw to it that for the year of the deluge, representatives from all the earth's creatures will live together in perfect peace and harmony (or at least near-perfect harmony, according to the famous Midrashic passage of the lion that bit Noach's hand). As He flooded the earth, God also sowed the seeds of its reconstruction by demonstrating the ability of people and even animals to live together amicably in the cramped, crowded confines of an ark. This arrangement served as a precedent to the possibility of peaceful relations among people and even between man and beast. It proved that the world is not necessarily condemned to a state of chamas; violence and conflict are not essential ingredients of the human condition. Just as all creatures on the ark lived together harmoniously, so is it possible for mankind to lead a peaceful life and build and cultivate the earth with mutual respect and cooperation.