Malbim (Tehilim 18:23): Mishpat is what intellect obligates. Chok is what intellect does not understand. Negdo is opposite the person, outside of him. "Lo Asir Mini ¹ " shows that it clings to him, and he does not cast it off. The Mishpatim are Negdi - I do not keep them because my intellect says so, rather, because Hashem commanded them. It is as if they are opposite me, not in me; I accept them from Hashem, like matters far from intellect. I view the Chukim as if they are in my intellect, and not outside of me - "Natisi Libi La'asos Chukecha" (Tehilim 119:112). Amidst his Eumnah in Hashem, his heart is drawn to them like Mitzvos that intellect obligates, to the point that I will not veer them from me; they are rooted in my heart and Nefesh.

Radak: [I will not veer] from every Mitzvah and statute.

Radak (Tehilim 18:23): I did not turn my heart to idle matters. I was always careful from every sin, with all my strength.