CC Ādi 4.102

avatari’ prabhu pracārila saṅkīrtana
eho bāhya hetu, pūrve kariyāchi sūcana
Word for word: 
avatari’ — incarnating; prabhu — the Lord; pracārila — propagated; saṅkīrtana — the congregational chanting of the holy name; eho — this; bāhya — external; hetu — reason; pūrve — previously; kariyāchi — I have given; sūcana — indication.
Translation: 
The Lord came to propagate saṅkīrtana. That is an external purpose, as I have already indicated.