I know that according to greek, penetrates means "occurrence"
Verb - Present Participle Middle or Passive - Nominative Masculine Singular
Strong's Greek 1338: To pass through (to), come through (to), pierce. From dia and the base of hikanos; to reach through, i.e. Penetrate.
There is nothing tricky about the Greek word "dividing" here.
Noun - Genitive Masculine Singular
Strong's Greek 3311: From merizo; a separation or distribution.
The "word" here is the concept of
Noun - Nominative Masculine Singular
Strong's Greek 3056: From lego; something said; by implication, a topic, also reasoning or motive; by extension, a computation; specially, the Divine Expression.
What does it separate?
it penetrates even to dividing soul and spirit
joints and marrow
it judges the thoughts and attitudes of the heart.
The soul is likened to joints while the spirit is likened to marrow. The marrow produces blood, and life or animation is in the blood. The spirit controls the soul which controls motions.
The soul is likened to thoughts and the spirit is likened to attitudes. One's attitudes determine the kinds of thoughts one would like to think on. Again, the spiritual attitudes control the soul which determines his thought life.
This describes the central role of the human spirit over his soul. The spirit is supernatural because it connects with the indwelling Spirit.