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.
Related Commentaries of 1 Corinthians 16:9
1 Corinthians 16:9
9 For a great door and effectual is opened unto me, and there are many adversaries.