7. And the angel of the church in Philadelphia write, These things saith He that is holy, He that is true, He that hath the key of David, He that openeth, and shutteth; and shutteth, and no man openeth;
What is the key of David? I believe it is the key to the house of David.
2 Samuel 23:3-5
3. The God of Israel spoke, the Rock of Israel said to me, When one rules over men righteously, ruling in the fear of God,
4. He dawns on them like the morning light, when the sun rises on a cloudless morning, when the tender grass springs out of the earth, through clear shining after rain.
5. Truly does not my house stand so with God? For He has made an everlasting covenant, ordered in all things and sure. For will He not cause to prosper all my help and desire?
2 Chronicles 21:7 But the Lord would not destroy the house of David, because He had made a covenant with David and promised to give a Light to him and to his sons forever. Amp.
The house of David did fall into sin. None of his descendants were like David. The Lord had mercy upon the house of David. But the true Light that was given to them was the birth of Jesus Christ. He became the King of Kings and Lord of Lords and will always rule and reign in righteousness.
We can concentrate on David and learn his traits. He was a worshipper, always singing songs to the Lord. He fought Goliath and won when the Israelite Army was afraid.
He knew the Lord was with him wherever he went. He won victory after victory as he worshipped and danced before the Lord like none before him.
It says in 2 Sam. 23:5 that he will cause to prosper all my help and desire. Is that not what it says in Proverbs 16:3?
3. Roll your works upon the Lord–commit and trust them wholly to Him; He will cause your thoughts to become agreeable to His will and so shall your plans be established and succeed.
We know Jesus came and was born from the linage of David. His Light will always be connected to the house of David because of His earthly birth. His Everlasting Light will shine forever and ever as King of Kings and Lord of Lords.
When He gives us the key to the house of David, it is because we have been faithful in the small things that He has given us and like David He will always be the Light shining within us and will never fail us.