"Since you have kept my command to endure patiently, I will also keep you from the hour of trial that is going to come upon the whole world to test those who live on the earth. I am coming soon. Hold on to what you have, so that no one will take your crown." (Revelation 3.11)
With Christ coming soon, the ancient Philadelphians will be rewarded for their faithfulness. Christ's coming to Ephesus, Pergamum and Sardis will judge their evil ways. "I am coming soon," Jesus says. Until then, the Christian Church in Philadelphia is warned to hold on and be patient in adversity. The risen Christ tells them that he is coming quickly. This is a warning to the heedless and a comfort to the oppressed. James 5.8 comments, "You too, be patient and stand firm, because the Lord's coming is near." Jesus urges patient endurance of his people because he is due to come shortly, and then their distress will be at an end.
The risen Christ furthermore bids the Philadelphians to hold to what you have, that no one may "take your crown." It is not a question of someone stealing your crown but of God taking it from you and giving it to someone else, because you were not worthy to wear it.