EVERY LAST SOUL
The son of David will not come until the heavenly storehouse of souls is emptied. (Yevamos 62a; Rashi.)
G-d created a certain number of souls before creating the world. Each soul has its purpose and mission, and Moshiach cannot come until every last soul is born and carries out its duty. Every person reveals a new perspective on life and a new dimension of G-dliness. The birth of every child, therefore, brings us one step closer to Moshiach.
Sichos Kodesh Yud Shvat 5730 Seif 9
Sichos Kodesh Naso 5740 Seif 48