The Church at Philadelphia and Laodicea are the last 2 of the 7 churches that Jesus addresses before He shifts John's vision to His heavenly environ. To Philadelphia, Jesus says that He knows their deeds. Philadelphia was a church that did not fall prey to the persecution of outsiders under the pressure of Satan. Its problems were from "annihilation" (forces from within that degrade and weaken faith in Christ) from inside the church, very much like Smyrna. Like Smyrna, Jesus has no accusations against Philadelphia and indeed these are the only 2 churches of the seven churches that could say that. Jesus directly talks about those insider Jews, that were actually of the synagogue of Satan. Their influences wanted to taint the divinity and purpose of Christ. Jesus is going to spare Philadelphia from the trial that was coming to test the whole world. Remember these churches are representative or symbols of all churches worldwide and also of people worldwide. Jesus warns them not to let ANYONE take their crown which means that the ultimate power to decide our fate and faith is OUR choices.
Finally Jesus tells the Church at Laodicea that they are an "emetic", a substance that makes you throw up! In other words, they make Him sick because they are lukewarm. he needs them to be either hot or cold. Jesus has no approving words for Laodicea and He threatens to close the church down, like He threatened to close Ephesus down. Jesus is looking for "one that will be victorious". The instruction may be to the Church, but salvation is achieved individually! Jesus utters those famous words to Laodicea, "I stand at the door and knock! If anyone hears my voice and opens the door, I will come in and eat with that person." This is a stark message for all of the churches. Jesus is less concerned with what church we are associated with and VERY concerned with how we live and choose as individuals.
Each of the letters to the seven churches teaches a specific lesson for sanctification while we choose and work daily to acquire an intimate relationship with Jesus. As a practical matter, the geo-historical information is less important than the issues that Jesus raises and how those issues are adjudicated by HIM. So, knowing the crimes we commit against the Lord and how they will be judged can help us avoid those pitfalls by study, prayer, and supplication until we come into perfect peace with Him and the Kingdom that He and the Children of God will rule here on the earth. Amen.