“I know your works. See, I have set before you an open door, and no one can shut it" (Revelation 3:8).
The church at Philadelphia had been given an open door of opportunity. All they had to do was to walk through it and establish the kingdom of God on the other side. There is absolutely no rebuke in the particular letter from Jesus to the Christians in Philadelphia -- only encouragement, while they still had “a little strength” left to do good to all.
The church had many opponents. False teachers, Judaizers, and Satan himself pitted their wits against the little group of believers. But the believers kept true to their Lord and took the grand opportunity to draw on His strength and to step through those open doors.
God has opened doors of opportunity for us, too -- opportunities to witness freely, and to attend Bible classes, and growth groups; opportunities to have Christian friends and fellowship.
It’s impossible to stop God’s holding the door open. The only thing we can do is to stand still and refuse to enter through the door of service. You don’t need to be a very strong Christian to step over the doorstep and begin. You only need to have “a little strength” to do that! Incidentally, when you walk through the door, Jesus will meet you on the other side with a new power, a new blessing, and a new name(see v. 12)!