Why Do We Celebrate Two Days of Rosh Hashanah?

Rosh Hashanah is celebrated for two days - the simple reason is that in the times of the Beit Mikdash (Holy Temple), Rosh Hashanah was determined based on the testimony of witnesses, and since Rosh Hashanah occurs on Rosh Chodesh (the new month), there was uncertainty that witnesses might arrive in the middle of the day and reveal that the day is Rosh Hashanah. However, the Sages established that Rosh Hashanah should be observed for two days consistently because the judgment extends over two days, just like other holidays, which are observed for two days outside of Israel, Rosh Hashanah is also observed for two days by those living in the Land of Israel.

On the first day - it is a strict judgment, examining each person individually to determine if they are worthy of life. It is explained in the books that most do not emerge meritorious in the judgment of the first day. The second day - it is a weaker judgment, assessing a person in relation to the community, whether they help others, belong to the Jewish community, and assist the collective; in this judgment, it is easier to merit, for example - even if someone, heaven forbid, is not worthy of life for themselves, because they volunteer once a week to drive elderly individuals to prayer, for that elderly person in need of assistance for prayer, the driver merits life for all that this implies.

Therefore, a good counsel to merit in judgment is to find something that connects a person to the community and is needed for the public good.