God, being infinite, cannot be grasped by the mind, and whatever is grasped by the mind is certainly not God.
What the mind can experience, however, is Wisdom, that Sefirah which is not yet given to understanding.
And it is in Wisdom that the light of the Infinite is vested.
There is an anecdote which, however crude, expresses an aspect of this idea.
When the Rabbi of Kotzk was asked "to explain why God did this or that, he answered in his own blunt fashion: "A God whom any stinking human can understand is not worth worshiping."
In other words, if reason is satisfied concerning the Divine, it has not attained anything consequential.
Nevertheless, there is a higher, if hidden, grasping of the Divine, which is given to every person to understand, even the unlearned.
This is expressed in a faith that is itself enlightenment.
In Proverbs 14:15, we find: "The simple (man) believeth everything, but the prudent man understandeth."
Faith is, thus, not a matter of simple believing but of that special quality which goes beyond the mind, which is of wisdom–that is to say, it is an experience directly connected with the Divine and not with knowing this or that about Him.
Therefore, the fact that a person is unlearned or even lacking in intellectual capacity makes no difference.
One's faith is not nourished by the mind but by wisdom of the soul; so that faith is available to all men, irrespective of their mental abilities.
–Rabbi Adin Steinsaltz
From "On Faith and Maryrdom" in The Long Shorter Way by Rabbi Adin Steinsaltz