“You graciously endow man with wisdom.”
What would man be without wisdom and knowledge? Indeed, it is only the gift of comprehension and discernment that distinguishes him from the animals of creation. In yet a deeper sense, without the faculty of knowledge man would forever be lacking the most basic ability to perceive his own existence, not to mention the ability to realize any of the other gifts of life. Regarding this the Sages teach: “He who has knowledge has everything. He who does not have knowledge has nothing.” What's more, without the faculty of knowledge man would not even be able to pray. Hence, it is fitting that the first of our requests be for wisdom.
When a child is asked what he wants he responds with a list of his favorite toys and sweets. So too, a fool who lacks understanding and foresight, when asked what he would like, will ask for foolish things. In contrast, when a wise man is asked he will answer in accordance with his wisdom, taking into account tomorrow's outcome of today’s requests.
What’s more, all of one’s experiences are ultimately influenced by his perception. When one’s knowledge is twisted and perverted, then all that he encounters in life will be gauged by his warped views. However, someone with true wisdom will evaluate all things through a lens of truth.
It is therefore necessary to first acquire true wisdom in order to view both the world and one’s own life correctly, and only afterwards ask for one’s needs. In this way one will beseech G-d to endow him with the wisdom to ask for the right things, and for the understanding to use them only in a proper and beneficial manner.
To be Deserving of Mercy
According to the above we can understand a difficult teaching in the Talmud which states that it is forbidden to have mercy on someone devoid of understanding, such as a fool, in accordance with the verse: “Because it is a nation devoid of understanding, therefore, its Maker will not show it mercy, and its Creator will not be gracious unto it”. (Isaiah 27:11)
To show grace and mercy to someone devoid of the necessary understanding to perceive and appreciate G-d’s goodness would be a waste. In fact, our appreciation of G-d’s mercy is part of what helps us merit G-d’s blessings.
Another explanation: The Ben Ish Chai explains that it is certainly permitted to help someone who lacks understanding. Rather, the grace and mercy referred to here is the giving of undeserved power and authority. A person lacking the basic level of understanding will likely misuse whatever power he is given — in some cases even causing him and others harm.