A completely righteous person is not only someone who does no evil in deed, word, or thought.
Rather, he is someone whose quintessential nature,
deepest yearnings, and most hidden desires are completely identified
with God.
He cleaves to Him with every fiber of his soul, experiencing
“a great love,” referring to the highest levels of closeness with God that
a person can attain.
Even so, the thoughts of the completely righteous
person, and certainly the thoughts of anyone on a lower level, cannot
truly grasp God.
That is to say, although every thought comprehends
something, a truly complete grasp of God does not exist.
Rabbi Adin Steinsaltz