תּוֹרָה קצ

The true Tzadik — who is the aspect of Moshe — regarding what went forth as a word from the mouth of Hashem to do — he has no free choice regarding this to do it.

Rather his primary free choice is to intend the will of Hashem Yisborach — and to understand His will, may He be blessed, in what He does not explicitly reveal His will.

In the aspect of: ""Moshe added one day of his own reasoning"" [Shabbos 87a]. For in this the free choice of Moshe was involved — to receive the Torah or not to receive it.

For it was impossible to receive the Torah except after three days — as it was in truth.

And Hashem Yisborach told him only two days. And Moshe himself had to understand through his own reasoning — and chose to receive the Torah — and added one day.