The shofar is associated with
the Akedah, Abraham's offering of
Isaac on Mount Moriah, as detailed in Genesis
22. Rabbinical tradition associates the left
horn of the ram as the "first trump" and the right
horn as the "last trump."
A distinguishing
feature of the celebration is the last, climactic
blast, the Teki'at Shofar.
This is not the usual series of short bursts,
signalling alarm or bad news. Rather, it is a long
blast, signalling victory or good news.
It is this last blast that is referred to as
"the last trump."