פירוש על מגילה 26:15

"They cast a pur": And what is a pur? "It is a lottery [...] concerning each day" - on which day the lottery will land. And likewise, "concerning each month." And he cast the lottery for all of them on one day; and the lottery landed on one day.

Moshe died on the seventh of Adar: As it is stated (Joshua 4:19), "And the people came up from the Jordan on the tenth day of the first month (Nissan)." Remove from them thirty days backwards for the mourning for Moshe; and three days that they prepared provisions for themselves. As it is stated (Joshua 1:11), "Prepare provisions for yourselves, for in another three days you are to cross, etc." Hence Moshe died on the seventh of Adar.

And he was born on the seventh of Adar: As it is written (Deuteronomy 31:2), "A hundred and twenty years old am I today" - today completed my days and my years. The birth is worthy to atone for the death.