והיה ביום ההוא יתקע בשופר גדול ובאו האובדים בארץ אשור ... (ישעי' כז-יג)
Yeshaya HaNavi relates that although Yaakov Avinu and his family endured numerous trials and tribulations in their long journey from Eretz Canaan to Egypt, to the desert, to Eretz Yisroel, and eventually into exile, Klal Yisroel will ultimately enjoy the day, “When a great ram’s horn shall be sounded, and the strayed who are in the land of Assyria and the expelled who are in the land of Egypt shall come and worship Hashem on the holy mount, in Yerushalayim.”
Chazal say that the aforementioned ram’s horn will come from the ram that Avraham Avinu sacrificed at the akeidah instead of his son Yitzchok. But Avraham Avinu sacrificed that ram as a korban olah which must be fully burned on the mizbeach, so how would there be anything left over for Klal Yisroel to use when Moshiach arrives?
The Ramban, Rabbeinu Moshe Ben Nachman zt”l provides us with a remarkable answer, that when the time comes for the ram’s horn to be used, Hashem will gather up ll the ashes from the burnt korban olah and piece them back together thereby enabling the horn to be used once again.
While this esoteric answer seems a bit uncharacteristic of the holy Ramban, it does serve to draw a similarity between the ingathering and reconstruction of the ashes of the horn in Messianic times, to the ingathering and defragmentation that will take place amongst the many different factions of Klal Yisroel in those times.
May those days come speedily and in our days.