3 Bible Verses about Open Doors

"And write [this] to the angel of the church at Philadelphia: These are the words of Him who is holy and true, [and] who possesses the key [i.e., the power and authority] of King David, [and] who opens [a door] which no one will close, and who closes one that no one will open: I know about your deeds. (See, I have placed before you an open door, which no one can close). [Note: This probably refers to their being assured of some unspecified opportunity]. [I know] that you have [only] a little bit of strength, but [in spite of that] you have obeyed my word and did not deny my name.

because a great door [of opportunity] has opened up to me [here] for doing an effective work [for God], but there are [also] many enemies who oppose me. [See Acts 19].

Now when I came to Troas [See Acts 16:8], in order to preach the good news about Christ, and when a door [of opportunity] was opened to me in [the service of] the Lord [there],