One day during the Holocaust, after a grueling workday in a slave labor camp, R' Yechiel Michel Schlager and R' Moshe Nosson Notta Lemberger engaged in conversation. R' Schlager shared with R' Lemberger the following calculation.
The gemara says that Moshiach will not come until there are no more souls in guf (the name of a chamber in Heaven that is inhabited by the souls waiting to be born). Moshiach will not come until all the souls there are born. R' Schlager explained, “If a person doesn’t fulfill his potential, then his soul must undergo reincarnation, and this prevents a new soul from being born. Because Hashem saw that there were an immense number of souls waiting in guf, this is what had to happen. The six million kedoshim will surely not need to undergo reincarnation, thereby permitting the birth of new souls.”
In conclusion, the six million kedoshim paved the way for the birth of new souls, ultimately facilitating the arrival of Moshiach sooner.
