On the face of it the Christians in Philadelphia were in a pretty bad situation but as more and more doors were shutting to them Jesus says “I have a key you might be interested in.” Specifically it is the key of David.
Once again we find Jesus making an exclusive claim. There are no duplicates of this key and no one else has it. If Jesus unlocks a door no one can shut it again. If Jesus locks a door no one can open it. But what are the doors and where to they go to? To help answer that we need to know a little background.
David was a king of Israel, whose rule and reign and kingdom marked a high point in the history of Gods people in the OT. It didn’t last but pointed forward to a greater kingdom with a greater king. The key to the house of David was the key of access to this perfect king and his everlasting kingdom. But we can be a little more specific here as Jesus is quoting from Isaiah 22.
Hundreds of years ago, God’s people were held up in the city of Jerusalem while enemy forces shook the ground outside them. They were at one time overly confident in their own defenses and at another resigned to party and make the most of life before they died. In both perspectives they excluded God.
God spoke to them saying that he would give them a new steward called Eliakim, second only to the king, who in contrast to his predecessor was not self regarding and ostentatious but a servant of the lord, and a father to the people. Not unstable rolling around like a ball, but stable like a peg driven into a solid place. Not bringing disgrace but glory to God’s rule and his ways.
And I will place on his shoulder the key of the house of David. He shall open, and none shall shut; and he shall shut, and none shall open. And I will fasten him like a peg in a secure place, and he will become a throne of honor to his father’s house. Isaiah 22:22-23 (ESV)
Eliakim was given authority to govern the kingdom. To let people in and to keep people out. To determine who got to speak to the king and who was excluded from his presence.
Jesus is saying I am the true and greater Eliakim. I am God’s good and perfect steward with the key not to a crumbling earthly kingdom but an enduring heavenly one. Jesus is claiming to be the true servant of the LORD, the one who will bring glory to his father’s house by laying down his life for his people. He is telling them not to look to your own strength, nor despair in their weakness, but to take hold of Him, the peg in a solid place that can be relied upon. That peg was a cross driven into the ground and upon which the LORD Jesus was crucified. Our sin and shame was hung on him and he is the way to the kingdom and the King.