Jesus has set a door before us that no one can shut - Revelation 3:8

I know thy works: behold, I have set before thee an open door, and no man can shut it: for thou hast a little strength, and hast kept my word, and hast not denied my name.

This verse is in the midst of Christ’s words of praise to the church at Philadelphia. Because they had been faithful, zealous for good works, and trusted in the Lord, they had been able to preserve the truth by living it out in their lives. Therefore, Christ would set before them an open door of opportunity that no one would be able to shut.