CC Madhya 13.64

kabhu eka mūrti, kabhu hana bahu-mūrti
kārya-anurūpa prabhu prakāśaye śakti
Synonyms: 
kabhu — sometimes; eka mūrti — one form; kabhu — sometimes; hana — becomes; bahu-mūrti — many forms; kārya-anurūpa — according to the program of activities; prabhu — Lord Śrī Caitanya Mahāprabhu; prakāśaye — exhibits; śakti — His internal potency.
Translation: 
According to His need, the Lord sometimes exhibited one form and sometimes many. This was being executed by His internal potency.