Finishing the מאמר, the רבי explains the underlying theme of the two interpretations of "דילה הוו חיין" - owning your life through תשובה מאהבה, and מלכות being able to express itself with ביטול:

When the שרש is revealed, it brings about the unlimited power of being able to handle opposites, drawing down from higher than time into time, and the ביטול עצמי into expression.

Continuing in the מאמר, the רבי fuses together the explanations of זהר and רש"י on "שני חיי שרה" in the opposite way as before - through "כולן שוין לטובה" one can reach "דילה הוו חיין":

When the source of מלכות is revealed, not only do the other ספירות benefit from it, מלכות itself becomes redefined. Instead of selflessness (ביטול) in contradiction to expression, מלכות can now express itself selflessly.

In our עבודה this means the ability to feel joy: not in contradiction to our selflessness to Hashem, but on the contrary - expressing it!

Link to Text Sheet PDF here.

In this extended שיעור, we continue the מאמר, where the רבי applies the lesson we learned from רש"י to answer a famous question in תניא.

To better appreciate this answer, we present the background of this question, and the various answers posed prior to this מאמר, slowly developing the tremendous חידוש the רבי is teaching us here.