1 Corinthians 16:9

For a great door and effectual is opened unto me, and there are many adversaries.
— 1 Corinthians 16:9, King James Version

In other translations

World English Bible (WEB)

for a great and effective door has opened to me, and there are many adversaries.

American Standard Version (ASV)

for a great door and effectual is opened unto me, and there are many adversaries.

Young's Literal Translation (YLT)

for a door to me hath been opened--great and effectual--and withstanders <FI>are<Fi> many.