Moshe tried to convince Paroh to let the Jews go for 3 days to serve Hashem.
Paroh finally said: לכו נא הגברים. [Only the men can go.]
That is apparently the Biblical source for men to go to Uman.
"אלול" ראשי תיבות - א'בא ל'אומן ו'אמא ל'בד
