This holiday is the first of the Yamim Noraim (Hebrew, "Days of Awe"), the most solemn days of the Jewish year; the Yamim Noraim are preceded by the month of Elul, during which Jews are supposed to begin a self-examination and repentance, a process that culminates in the ten days of the Yamim Noraim known as Asseret Yemei Teshuva - The Ten Days of Repentance, beginning with Rosh Hashanah and ending with the holiday of Yom Kippur.This day is also called "The Feast of Trumpets."
I think, as an act of solidarity with our ancestors of the Old Covenant and with Hebrew Catholics who still highly regard the Jewish Calendar, it is good for us learn more about these Jewish holy days, in the very least, so that we can be conversant with any Jews that we may happen to meet throughout our daily lives. Conversion to Jesus Christ simply cannot take place in any of our encounters with Jews if we do not even respect them enough to learn a little bit about their spirituality. And yes, the Jews must be converted.
Here are some links to aid you in that regard:
- New Advent: Feast of Trumpets
- Jewish Encyclopedia: Rosh Hashanah
- Wikipedia: Rosh Hashanah
- Rosh Hashanah: Head of the Jewish Year
- Judaism 101: Rosh Hashanah
- Elul and Rosh Hashanah
- Orthodox Union: Rosh Hashanah
- Jewish Outreach Institute: Rosh Hashanah
- Rosh Hashanah for Children