From Chabad.org: The High Holidays are discussed. We are commanded to hear the shofar (ram’s horn) on Rosh Hashanah, and to “afflict” ourselves on Yom Kippur.

This Aliya isn’t very long, but it does include the instruction to hear the shofar because it’s a “zichron Truah”, or loosely translated as “sounds to remember”. What memories will these sounds conjure? Rashi explains that it’s the sacrifice Avraham was willing to make by offering his son Yitzchak. But the memory isn’t for the sacrifice itself, because it wasn’t us that made the sacrifice, it was Avraham. The shofar represents G-d releasing Avraham of the sacrifice he was willing to make. What was left, and what should be emulated,  was the willingness to sacrifice, and the knowledge that G-d has our backs.