Not everyone has the requisite intellectual capacity to “know and contemplate the greatness of Ein Sof”.
Moreover, even if a person does possess this ability, it does not necessarily follow that he can generate a revealed sense of love, fear, and trepidation.
A clear intellectual grasp and comprehension can result in different degrees of emotional involvement, none of which will necessarily be expressed as an emotional response.
There are people who find it difficult or impossible to grasp abstract concepts, and when they try to contemplate God, they contemplate some reified image, each person on his level.
But even if a person were to have a clear, physical image, to whatever degree of physicality, this still will not necessarily lead him to an experiential and emotional connection.
This can be observed in children engaged in prayer.
There are children who in their minds can imagine God and can achieve a sense of deep emotional involvement.
By contrast, there are children who, while also capable of imagining God (according to their perception), are nevertheless unable to use that image to create a relationship, neither emotional nor intellectual.
Rabbi Adin Steinsaltz