avatāra-kārya - mission of the incarnation; prabhura - of Śrī Caitanya Mahāprabhu; nāma-pracāre - spreading the importance of the holy name of the Lord; sei - that; nija-kārya - mission of His life; prabhu - Śrī Caitanya Mahāprabhu; karena - performs; tomāra dvāre - through you.

“The mission of Śrī Caitanya Mahāprabhu, for which He has descended as an incarnation, is to spread the importance of chanting the holy name of the Lord. Now instead of personally doing so, He is spreading it through you.