The wisdom of the serpent and the simplicity of the dove are a paradoxical combination even at first glance. It becomes still more paradoxical when examined more carefully. For the issue here is clearly the very serpent who tempted the first people in the Garden of Eden. It is he who is called "wise" in the biblical account of the fall. Or, more precisely, "prudent," "cautious": this is exactly what the corresponding Hebrew word in the account means. The same is true of the Greek word from the Savior's speech addressed to the apostles.
The same "prudence" belongs to the wise person as well, at least as Proverbs says of the wise. Translators call the serpent "crafty," but when the same word refers to a person, they more often call this person "prudent," and sometimes, as in our Gospel passage, even "wise."
But the issue is clearly not definitions. In essence the issue is one and the same: the ability to see the world as it is. With all its pluses and minuses. With all its possibilities, even those that can be used for evil. The ability to distinguish white and black, light and darkness. And to understand the logic of action both of the forces of light and of the forces of darkness. If only so as not to be deceived about those who have chosen the side of darkness. But this knowledge alone is not enough. The serpent who tempted the first people had such knowledge too. By itself it still does not save from evil.
What is also needed is the wholeness and purity (these are the qualities denoted by the corresponding Greek word) of the turtledove, the wild dove, the only bird suitable for every sacrifice, including a cleansing one. That wholeness which will allow one to make a choice and take a decision relying not on the wisdom of this world, so well known to the one choosing, but on the will of God. And that purity which allows one, while seeing all the evil of the world as it is, not to look back at it at all when the matter concerns God's work.
The prudence of this world is useful when analyzing a situation, but it becomes spiritually destructive when one must choose and make decisions following God's will, decisions corresponding to the Torah and the Gospel. The Kingdom of God is a reality, not a pious fantasy or a religious symbol, and therefore the one who seeks it must be a realist. But his realism must not be limited only to the realities of the fallen world, as often happens with the realists of this world. Then the Kingdom too will become a reality for such a person, a real goal that can be reached.