The Rebbe expresses joy over the achievement of 300 students in Yeshivas Achei Tmimim and encourages setting a higher goal of 500 and beyond. He emphasizes that success depends only on willpower, especially in Kislev, a month of victory. He blesses the administrator and his wife with true nachas and continued success.
https://www.torahrecordings.com/rebbe/igroskodesh/014/003/4887