Continuing in the explanation of חוקים, the רבי presents a fascinating difference between עדות and חוקים:

While עדות is "רעותא דלבא" - the connection to Hashem from the deepest core of the person's self (his עצם הנשמה), חוקים is putting one's self on the side and serving Hashem with קבלת עול.

Consequently, while עדות is the idea of עצמות being expressed within the world, חוקים is the idea of a איד connecting with Hashem's Essential Desire - רצון עצמי, beyond any function of expression.

This all explains why "חוקיך" is emphasized in the פסוק describing תורה's greatness - "זמירות היו לי חוקיך".

However...