“For a great door and effectual is opened unto me, and there are many adversaries.”
King James Version (KJV)
16:9 A great door - As to the number of hearers. And effectual - As to the effects wrought upon them. And there are many adversaries - As there must always be where Satan's kingdom shakes. This was another reason for his staying there.
1Co 16:9 For a great door and effectual is opened. His ministry in Ephesus was very successful. See Ac 19:20. There are many adversaries. Demetrius and his fellow-craftsmen had probably begun their agitation (Ac 19:23-41).