Summary: Due to their rejection of Christ, the Jews lost their position as being God's Chosen. The Church, composed of the believing Jewish Remnant and Gentiles, is now God's Chosen. Christians, alone, have access to the throne of God.
Verse 7 – Again, we see that this letter is sent to the angel of the church; that is, to the leadership of the congregation in Philadelphia.
In the other Letters to the six other congregations, Jesus introduced Himself by taking phrases from the vision of Christ in Chapter 1. This is not the case with this Letter. It seems that there wasn't a descriptive phrase from the 1st Chapter that would suit in dealing with the situation in Philadelphia..
First, Jesus says He is the Holy One. The Jewish Christians in the Philadelphia congregation would understand that Jesus is claiming to be the God of the Old Testament Who identified Himself using the same title. I want to quote from Isaiah 43:15, “I am the Lord, your Holy One, the Creator of Israel, your King.” Here, we find that the Holy One is the true King of Israel. This very important fact needed to be understood by the Philadelphian brethren as we shall see.
Second, Jesus says He is One “Who is true.” Jesus is the embodiment of Truth. As He said in John 14:6, “I am the Way, the Truth, and the Life.” God revealed a portion of truth through Moses and the Jewish Prophets. However, all Truth is revealed in the life and teachings of Jesus. The apostate Jews are liars, says verse 9, but Jesus reveals that which is true.
Thirdly, Jesus says that he “has the key of David.” What does this mean? The explanation is provided in Isaiah 22:15, 19-22, “Come, go to this steward, to Shebna, who is in charge of the royal household... I will depose you from your office, and I will pull you down from your station. Then it will come about in that day, that I will summon My servant Eliakim, the son of Hilkiah, And I will clothe him with your tunic and tie your sash securely about him. I will entrust him with your authority, and he will become a father to the inhabitants of Jerusalem and to the house of Judah. Then I will set the key of the house of David on his shoulder, when he opens no one will shut, when he shuts no one will open.”
The office that Shebna held and was about to be given to righteous Eliakim was, for lack of better words, gatekeeper of the Royal Throne Room. He was in charge of who was and who wasn't allowed to enter into the presence of the King. He had the key. He had full authority to open the door for worthy people to enter. When he opened that door, no one had the authority to shut it. He also had full authority to close the door to unworthy people. When he shut the door, no one had the authority to open that door.
Jesus tells the Philadelphians that He now has the “key of David'; that is, Jesus has the full authority to open the door to enter into the King's presence to those who are deemed worthy and He has they full authority to close the door to enter into the King's presence to those deemed unworthy.
What is the significance of this reality to the Philadelphia brethren? In Philadelphia, there was a large population of Jews. It is obvious, from verse 9, that the non-Christian Jews of the synagogue were terribly persecuting the congregation, especially those in the congregation who formerly were practicing Jews.