Likutei Sichos – Vol 17 p 057 ff – Shabbos is about Ishapcha

Likutei Sichos – Vol 17 p. 57 ff.
Shabbos is about Ishapcha, transformation. The idea of time being a creation and the transformation on time to above time each Shabbos.
Why Shabbos HaGadol is ON Shabbos and is CALLED Shabbos.
It is the highest idea of אתהפכא Ishapcha, darkness is transformed to light while still dark, because only then is it truly Ishapcha. In Egypt there was a civil war that was a great miracle for the Jewish people who remained IN Egypt even after the event. True Ishapcha is connected inexorably to Shabbos.