Reasons for the ban:
1. If we’re meritorious we can bring Geula faster, so leaving the date open keeps it in our hands to speed things up.

2. Not knowing the exact date keeps us yearning, preparing, and expecting it any moment,

3. Connects exile with redemption

Why did tzaddikim predict end-times despite the ban:

1. Uplift Spirits: Predictions strengthened faith in dark times, like Rambam’s era vs false messiahs.
2. Proximity to Geula: The prohibition loosens as we get closer. Ramban uses this for the date in Sefer HaGeula.
3. Type of calculation: The ban is on astrology/constellations, not words of Neviim. Abarbanel: wanting the end-time shows genuine desire for Geula.
4. Authority: High-level tzaddikim are permitted to calculate and judge if revealing helps or harms. Regular people lack that judgment, so it can cause panic, despair, or false hope.
5. Source of Prediction: Tradition/reliable sources vs. personal calculations with no backing.

Clarification: Saying “this era is the time of Geula” isn’t under the prohibition. That’s why Chachamim gave signs for “ikvisa demeshicha.”

(Sefer Hasichos 5750:2 398, Likutei Sichos 29 p. 16, Likutei Sichos 23 p. 396)