On the third day, Tiferet, which is central column went down to become female of the central column by Moses. This is the secret of “Moses Bride”.
When it said (in the Mount Sinai event) “And on the third day, in the morning…” it describes the joining of the Two Tablets, face to face as supernal Netzach and Hod and create “אמת ליעקב”, “Truth to Jacob”, which is the continuation of upper to lower through the united pair of Netzach and Hod to Yesod as the Torah,
The Torah was given on the Seventh Day, Shabbat, and that bring Yesod in completion with Malchut.
Also it reveals the Light of Chokmah through the Torah.
As God said to Moses (Exodus 33:23) “And you will see my back and not my face (also mean inner)…”. This means that to get to the inner lights we must dwell in the Torah and elevates ourselves.
מקור הקטע: הקדמת תיקוני הזוהר עם פרוש מעלות הסולם (רבי יהודה צבי ברנדויין זל) פסקה 248